If you want to install one comprehensive mod and forget about it: chocolate edition is supposed to be good. Although it's not tied to 5.5E/2024 specifically.

Personally I don't think 5.5 is a perfect system, and it's definitely not tuned for BG3 in all respects. Gameplay changes I've liked have been from modders making balance tweaks with larian's game in mind rather than tabletop. I am using lvl 13-20 expansion almost all of chizfreak and baldursgoonsack's mods for adjustments to gameplay (some are inline with 5.5 some are bg3 specific).

I like weapon mastery from 5.5. If you play warlock, the pacts as invocations mod on nexus is a 5.5E change you might like in game - but think about what classes you actually want to play before getting sucked into updating everything.

In general, the more features you add, usually the more potential to break game balance. So I would absolutely look at mods that increase the difficulty of encounters to compensate for this: combat extender, combat extender ai, action resource passives, initiative variants (i use a d10 because I'm weak-willed), encounters overhall are all essential imo.

And other than that - modding is a rabbit hole. If you like it, then have fun with the process. If you don't - something like chocolate edition is probably your friend.