archinstall is good yeah, it would be nice if it had a proper graphical install rather than the console ui. I think less technical people would be put off by it.

Use the nvidia one im pretty sure. I think it will come with the proprietary nvidia drivers preinstalled

PopOS, Mint, Ubuntu are the main ones recommended for new users, just try them out and see what you think. I personally used Ubuntu for about half a year and then moved over to Archlinux and have been using arch for like 4 years now, but arch is too hard for new users so dont try it.

mainly just using steam, and if i need to i use lutris. tried bottles a few times but its kinda buggy for me