I'd be all for a keyring, but there's a reason if they don't want to do it, and that's the same of plenty of bad features about these games: multiplayer.
They WANT to have each key as a separate item since its their way to allow players to pickpocket each other, compete etc.
Doesn’t BG3 have “magic pockets”? I am pretty sure that in D:OS2 keys would get automatically transferred between party members if they tried to access appropriate doors. This certainly happened in singleplayer, but I am pretty sure it worked that way in coop as well.
