You said BG3 was a gift, so it’s not costing you anything to not play something you don’t like.
Given what you’ve said, I would suggest avoiding anything with an RPG label anywhere.
For BG3, if you want to keep playing, you can skip the character creator. They have a dozen prebuilt options you can play without doing the detail work.
For inventory, you can ask your brother to handle it and send everything to camp.
But even with those, you’ll likely not enjoy BG3 because even the fighting mechanics are based around that type of complex decision making, making you pause all the time so that you can make those decisions.
It’s ok to tell your brother you don’t enjoy the gameplay. You don’t have to like it just because other people do.