i am trying to plan a social event but everytime its blank and before you ask yes i went through the painful task of doing the 50/50 method and its just confusing so i tried my best so i need super help please

Searching trough MCCC discord channel seems like some trait was causing this issue for someone, but they didn't mention which
I would try without any cc traits first to see if that helps.

any other UI mods (UI cheats, cc events, careers etc..)? try without those as well, if traits wasn't the issue.

do you get any LastException file in your Sims 4 folder?
if you do you might want to go drop it at MCCC discord channel, as it can help figuring it out.
https://discord.gg/h6GkGyd