They’re very different, so you need to figure it out for yourself. Both are great, but we don’t know your tastes. I would recommend BG3 though, for what is worth.

However, if you’re strapped for cash, I would recommend playing indie games. They’re often more interesting than these larger budget games (though these two are exceptions to large budget games being shit), and they’re usually like $20 max. Most people can get more out of Factorio or Dwarf Fortress, for example, than they can out of these games, at a much lower price.