I reckon you could play just base game but i would recommend getting at least expansions cause ones out rn are usually really cheap for the amount of new content you'll have. I just wouldn't play without them now cause I already have them and would get no benefit from doing so.
But say I was using a cheap laptop instead, I'd likely only use base game cause it'll have better performance.
Also as someone who doesn't like using cc (I only use gameplay mods) I like having more content that won't be deleted from a lot if accidentally loaded after an update. I know I can move and move back cc for an update but I forgot all the time when using cc hair and ended up with bald sims everywhere too many times.
