Soo....

If you have a mod that changes the main menu, I recommend removing it; it’s usually a CC file labeled “main menu overrides.” But that will only fix the main menu—if the game is glitching, check your mods (it took me three hours to get the game to launch without error messages, and EA is just telling me to find the updated version of a CC file I released back in 2019. Gurll, I’m not even sure if the CC creator is still around.)

my pc idk if other pcs have it but open ur taskmanger then close sims 4 it just forces apps to close almost instantly

i had this issue too. just restart your computer. it was the only way i found to exit. its a problem with outdated mods since the marketplace update (it was for me at least)