This idea primarily is for people who have terribad PCs. Maybe this could be added as a launch option for the game, but the premise is simple: Whenever a Quest version of an Avatar/World is available, let the PC user see that instead of the PC version. If not, then just use the PC version of the avatar/world.
Not only do I think this would help people on poor performance computers, but I also think it would be handy for avatar creators who only have PCs and upload Quest available versions (me being one of them) of their avatars, too. Maybe you can already see Quest avatars/worlds on PC, but as far as I'm aware you can't.