there's no timetable for BIP324 being merged that I'm aware of, but it's development has been in the works several (5?) years now.
BIP324 was created only 4 years ago, but it seems some function for it has been created since 5 years ago[1]. In any case, with amount of open PR/total line changes i don't expect it'll ready anytime soon.
[1]
https://bip324.com/sections/code-review/