diff --git a/packages/core/components/AutoFrame/index.tsx b/packages/core/components/AutoFrame/index.tsx
index a0d8580f4c..5e15619ee2 100644
--- a/packages/core/components/AutoFrame/index.tsx
+++ b/packages/core/components/AutoFrame/index.tsx
@@ -6,11 +6,24 @@ import {
   useEffect,
   useState,
 } from "react";
-import hash from "object-hash";
 import { createPortal } from "react-dom";
 
 const styleSelector = 'style, link[rel="stylesheet"]';
 
+/**
+ * Fast, non-cryptographic djb2 hash over a string.
+ * Replaces `object-hash` which serialises the full outerHTML via JSON
+ * and is O(n) on the CSS string length — catastrophically slow when
+ * many large style nodes are present.
+ */
+const fastHash = (str: string): string => {
+  let h = 5381;
+  for (let i = 0; i < str.length; i++) {
+    h = (((h << 5) + h) ^ str.charCodeAt(i)) >>> 0;
+  }
+  return h.toString(36);
+};
+
 const collectStyles = (doc: Document) => {
   const collected: HTMLElement[] = [];
 
@@ -66,6 +79,25 @@ const syncAttributes = (sourceElement: Element, targetElement: Element) => {
 
 const defer = (fn: () => void) => setTimeout(fn, 0);
 
+/**
+ * Compute a cheap hash key for a style element.
+ * - For <link> elements we key on the href (a short string).
+ * - For <style> elements we key on the CSS text content plus any attributes
+ *   (e.g. nonce, data-*) so that two tags with identical CSS but different
+ *   attributes are not incorrectly treated as duplicates.
+ * We deliberately avoid hashing outerHTML because it includes the full
+ * serialised CSS blob and was the primary source of the 30-45 s freeze.
+ */
+const styleElHash = (el: HTMLElement): string => {
+  if (el.nodeName === "LINK") {
+    return `link:${(el as HTMLLinkElement).href}`;
+  }
+  const attrs = Array.from(el.attributes)
+    .map((a) => `${a.name}=${a.value}`)
+    .join(",");
+  return `style:${fastHash(el.innerHTML)}:${attrs}`;
+};
+
 const CopyHostStyles = ({
   children,
   debug = false,
@@ -144,13 +176,7 @@ const CopyHostStyles = ({
         return;
       }
 
-      const mirror = await mirrorEl(el);
-
-      if (!mirror) {
-        return;
-      }
-
-      const elHash = hash(mirror.outerHTML);
+      const elHash = styleElHash(el);
 
       if (hashes[elHash]) {
         if (debug)
@@ -161,6 +187,11 @@ const CopyHostStyles = ({
         return;
       }
 
+      const mirror = await mirrorEl(el);
+      if (!mirror) {
+        return;
+      }
+
       hashes[elHash] = true;
 
       doc.head.append(mirror as HTMLElement);
@@ -180,14 +211,45 @@ const CopyHostStyles = ({
         return;
       }
 
-      const elHash = hash(el.outerHTML);
+      const elHash = styleElHash(el);
 
       elements[index]?.mirror?.remove();
       delete hashes[elHash];
 
+      // Must splice so lookupEl doesn't return stale entries for nodes that
+      // were removed and later re-added (e.g. on remount), and to avoid
+      // unbounded growth of the array over the lifetime of the observer.
+      elements.splice(index, 1);
+
       if (debug) console.log(`Removed style node ${el.outerHTML}`);
     };
 
+    // Batch pending mutations so that a burst of style injections only
+    // triggers a single round of addEl/removeEl work instead of one
+    // synchronous call per node.
+    let pendingAdded: HTMLElement[] = [];
+    let pendingRemoved: HTMLElement[] = [];
+    let flushTimer: ReturnType<typeof setTimeout> | null = null;
+
+    const flushPending = () => {
+      flushTimer = null;
+      const toAdd = pendingAdded;
+      const toRemove = pendingRemoved;
+      pendingAdded = [];
+      pendingRemoved = [];
+
+      toRemove.forEach((el) => removeEl(el));
+      // addEl is async but we intentionally don't await here to keep the
+      // flush non-blocking; each addEl checks hashes before touching the DOM.
+      toAdd.forEach((el) => addEl(el));
+    };
+
+    const scheduledFlush = () => {
+      if (flushTimer === null) {
+        flushTimer = defer(flushPending);
+      }
+    };
+
     const observer = new MutationObserver((mutations) => {
       mutations.forEach((mutation) => {
         if (mutation.type === "childList") {
@@ -202,7 +264,8 @@ const CopyHostStyles = ({
                   : (node as HTMLElement);
 
               if (el && el.matches(styleSelector)) {
-                defer(() => addEl(el));
+                pendingAdded.push(el);
+                scheduledFlush();
               }
             }
           });
@@ -218,7 +281,8 @@ const CopyHostStyles = ({
                   : (node as HTMLElement);
 
               if (el && el.matches(styleSelector)) {
-                defer(() => removeEl(el));
+                pendingRemoved.push(el);
+                scheduledFlush();
               }
             }
           });
@@ -253,10 +317,22 @@ const CopyHostStyles = ({
           hrefs.push(linkHref);
         }
 
+        // Deduplicate style nodes before mirroring: if two <style> tags have
+        // identical content, only mirror the first occurrence.
+        const elHash = styleElHash(styleNode);
+        if (hashes[elHash]) {
+          if (debug)
+            console.log(
+              `Skipping duplicate style node during initial collection...`
+            );
+          return;
+        }
+
         const mirror = await mirrorEl(styleNode);
 
         if (!mirror) return;
 
+        hashes[elHash] = true;
         elements.push({ original: styleNode, mirror });
 
         return mirror;
@@ -302,16 +378,13 @@ const CopyHostStyles = ({
       }
 
       observer.observe(parentDocument.head, { childList: true, subtree: true });
-
-      filtered.forEach((el) => {
-        const elHash = hash(el.outerHTML);
-
-        hashes[elHash] = true;
-      });
     });
 
     return () => {
       observer.disconnect();
+      if (flushTimer !== null) {
+        clearTimeout(flushTimer);
+      }
     };
   }, []);
 
diff --git a/packages/core/package.json b/packages/core/package.json
index b326e5b257..2711cd1e0e 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -80,7 +80,6 @@
     "@types/deep-diff": "^1.0.3",
     "@types/flat": "^5.0.5",
     "@types/jest": "^29.5.14",
-    "@types/object-hash": "^3.0.6",
     "@types/react": "^19.2.7",
     "@types/react-dom": "^19.2.3",
     "@types/uuid": "^10.0.0",
@@ -126,7 +125,6 @@
     "fast-equals": "5.2.2",
     "flat": "^5.0.2",
     "happy-dom": "^20.0.10",
-    "object-hash": "^3.0.0",
     "react-hotkeys-hook": "^4.6.1",
     "use-debounce": "^9.0.4",
     "uuid": "^9.0.1",
diff --git a/yarn.lock b/yarn.lock
index 3a59798a79..49b1722425 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4663,11 +4663,6 @@
   resolved "https://registry.yarnpkg.com/@types/normalize-package-data/-/normalize-package-data-2.4.4.tgz#56e2cc26c397c038fab0e3a917a12d5c5909e901"
   integrity sha512-37i+OaWTh9qeK4LSHPsyRC7NahnGotNuZvjLSgcPzblpHB3rrCJxAOgI5gCdKm7coonsaX1Of0ILiTcnZjbfxA==
 
-"@types/object-hash@^3.0.6":
-  version "3.0.6"
-  resolved "https://registry.yarnpkg.com/@types/object-hash/-/object-hash-3.0.6.tgz#25c052428199d374ef723b7b0ed44b5bfe1b3029"
-  integrity sha512-fOBV8C1FIu2ELinoILQ+ApxcUKz4ngq+IWUYrxSGjXzzjUALijilampwkMgEtJ+h2njAW3pi853QpzNVCHB73w==
-
 "@types/parse-json@^4.0.0":
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/@types/parse-json/-/parse-json-4.0.2.tgz#5950e50960793055845e956c427fc2b0d70c5239"
@@ -13638,11 +13633,6 @@ object-assign@^4.0.1, object-assign@^4.1.1:
   resolved "https://registry.yarnpkg.com/object-assign/-/object-assign-4.1.1.tgz#2109adc7965887cfc05cbbd442cac8bfbb360863"
   integrity sha512-rJgTQnkUnH1sFw8yT6VSU3zD3sWmu6sZhIseY8VX+GRu3P6F7Fu+JNDoXfklElbLJSnc3FUQHVe4cU5hj+BcUg==
 
-object-hash@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/object-hash/-/object-hash-3.0.0.tgz#73f97f753e7baffc0e2cc9d6e079079744ac82e9"
-  integrity sha512-RSn9F68PjH9HqtltsSnqYC1XXoWe9Bju5+213R98cNGttag9q9yAOTzdbsqvIa7aNm5WffBZFpWYr2aWrklWAw==
-
 object-inspect@^1.13.3, object-inspect@^1.13.4:
   version "1.13.4"
   resolved "https://registry.yarnpkg.com/object-inspect/-/object-inspect-1.13.4.tgz#8375265e21bc20d0fa582c22e1b13485d6e00213"
@@ -16352,16 +16342,7 @@ string-length@^4.0.1:
     char-regex "^1.0.2"
     strip-ansi "^6.0.0"
 
-"string-width-cjs@npm:string-width@^4.2.0":
-  version "4.2.3"
-  resolved "https://registry.yarnpkg.com/string-width/-/string-width-4.2.3.tgz#269c7117d27b05ad2e536830a8ec895ef9c6d010"
-  integrity sha512-wKyQRQpjJ0sIp62ErSZdGsjMJWsap5oRNihHhu6G7JVO/9jIB6UyevL+tXuOqrng8j/cxKTWyWUwvSTriiZz/g==
-  dependencies:
-    emoji-regex "^8.0.0"
-    is-fullwidth-code-point "^3.0.0"
-    strip-ansi "^6.0.1"
-
-"string-width@^1.0.2 || 2 || 3 || 4", string-width@^4.1.0, string-width@^4.2.0, string-width@^4.2.3:
+"string-width-cjs@npm:string-width@^4.2.0", "string-width@^1.0.2 || 2 || 3 || 4", string-width@^4.1.0, string-width@^4.2.0, string-width@^4.2.3:
   version "4.2.3"
   resolved "https://registry.yarnpkg.com/string-width/-/string-width-4.2.3.tgz#269c7117d27b05ad2e536830a8ec895ef9c6d010"
   integrity sha512-wKyQRQpjJ0sIp62ErSZdGsjMJWsap5oRNihHhu6G7JVO/9jIB6UyevL+tXuOqrng8j/cxKTWyWUwvSTriiZz/g==
@@ -16469,14 +16450,7 @@ stringify-entities@^4.0.0:
     character-entities-html4 "^2.0.0"
     character-entities-legacy "^3.0.0"
 
-"strip-ansi-cjs@npm:strip-ansi@^6.0.1":
-  version "6.0.1"
-  resolved "https://registry.yarnpkg.com/strip-ansi/-/strip-ansi-6.0.1.tgz#9e26c63d30f53443e9489495b2105d37b67a85d9"
-  integrity sha512-Y38VPSHcqkFrCpFnQ9vuSXmquuv5oXOKpGeT6aGrr3o3Gc9AlVa6JBfUSOCnbxGGZF+/0ooI7KrPuUSztUdU5A==
-  dependencies:
-    ansi-regex "^5.0.1"
-
-strip-ansi@^6.0.0, strip-ansi@^6.0.1:
+"strip-ansi-cjs@npm:strip-ansi@^6.0.1", strip-ansi@^6.0.0, strip-ansi@^6.0.1:
   version "6.0.1"
   resolved "https://registry.yarnpkg.com/strip-ansi/-/strip-ansi-6.0.1.tgz#9e26c63d30f53443e9489495b2105d37b67a85d9"
   integrity sha512-Y38VPSHcqkFrCpFnQ9vuSXmquuv5oXOKpGeT6aGrr3o3Gc9AlVa6JBfUSOCnbxGGZF+/0ooI7KrPuUSztUdU5A==
@@ -18125,7 +18099,7 @@ wordwrap@^1.0.0:
   resolved "https://registry.yarnpkg.com/wordwrap/-/wordwrap-1.0.0.tgz#27584810891456a4171c8d0226441ade90cbcaeb"
   integrity sha512-gvVzJFlPycKc5dZN4yPkP8w7Dc37BtP1yczEneOb4uq34pXZcvrtRTmWV8W+Ume+XCxKgbjM+nevkyFPMybd4Q==
 
-"wrap-ansi-cjs@npm:wrap-ansi@^7.0.0":
+"wrap-ansi-cjs@npm:wrap-ansi@^7.0.0", wrap-ansi@^7.0.0:
   version "7.0.0"
   resolved "https://registry.yarnpkg.com/wrap-ansi/-/wrap-ansi-7.0.0.tgz#67e145cff510a6a6984bdf1152911d69d2eb9e43"
   integrity sha512-YVGIj2kamLSTxw6NsZjoBxfSwsn0ycdesmc4p+Q21c5zPuZ1pl+NfxVdxPtdHvmNVOQ6XSYG4AUtyt/Fi7D16Q==
@@ -18143,15 +18117,6 @@ wrap-ansi@^6.0.1, wrap-ansi@^6.2.0:
     string-width "^4.1.0"
     strip-ansi "^6.0.0"
 
-wrap-ansi@^7.0.0:
-  version "7.0.0"
-  resolved "https://registry.yarnpkg.com/wrap-ansi/-/wrap-ansi-7.0.0.tgz#67e145cff510a6a6984bdf1152911d69d2eb9e43"
-  integrity sha512-YVGIj2kamLSTxw6NsZjoBxfSwsn0ycdesmc4p+Q21c5zPuZ1pl+NfxVdxPtdHvmNVOQ6XSYG4AUtyt/Fi7D16Q==
-  dependencies:
-    ansi-styles "^4.0.0"
-    string-width "^4.1.0"
-    strip-ansi "^6.0.0"
-
 wrap-ansi@^8.1.0:
   version "8.1.0"
   resolved "https://registry.yarnpkg.com/wrap-ansi/-/wrap-ansi-8.1.0.tgz#56dc22368ee570face1b49819975d9b9a5ead214"