Update
I was able to get this working in the daily build of the IDE by choosing a patched font in Preferences, e.g. see terminal window with FiraCodeNerdFontComplete selected below:
Old
If I use my default p10k setup in RStudio terminal (which also involves patched nerd fonts), I have the same result. I think this is due to the fact that not all fonts are supported in the IDE terminal (see, e.g. the issue from the IDE GitHub repo, below)
EDIT I can't actually figure out how to do what's suggested below for the RStudio terminal, as running echo $TERM_PROGRAM in the Terminal pane doesn't return anything.
You can disable/enable p10k in your zshrc based on what terminal program is being used (I do this for Warp, for example, which doesn't support powerlevel10k)
Not really a solution, but thought you might want to if the missing icons bug you.