R freezes when trying to extract marginal means from a GAMLSS fit

[robpetrosino]

I fit my data (~105,000 observations) to the following GAMLSS model:

exp1_fit_gaml <- gamlss(RT ~ frequency*primetype + 
                        re(random = ~1|subj) +  re(random = ~1|target),
                        nu.formula = ~ frequency*primetype + 
                        re(random = ~1|subj) +  re(random = ~1|target),
                        data=exp1_data_bay, family = exGAUS(),
                        control = gamlss.control(n.cyc = 50))

The line above runs perfectly and the estimates seem to make sense. However, when I try to extract the marginal means through either emmeans or marginaleffects, R freezes and the only thing I can do is to terminate the session and restart. Here's the code:

#emmeans
library(emmeans)
mu <- emmeans( exp1_fit_gaml, ~frequency*primetype, what = 'mu')

# marginal effects
library(marginaleffects)
grid <- datagrid(model=exp1_fit_gaml, by=c("frequency", "primetype"))
mu <- predictions(exp1_fit_gaml, newdata=grid, what='mu')

Can you help figure this out? Both packages should support gamlss, but there seems to be an issue here.