I’m a pack-rat in games and ive only hit the first (of three) stage of encumbrance two or three times in Baldur’s Gate and I’m in the final act. And my character is a bard with 8 strength so he has no muscles which means the lowest encumbrance threshold. I wouldn’t consider encumbrance even a little bit of a problem in BG3 since if you ever do become encumbered you can just move stuff from your player character to one of the NPCs used as a pack mule.