This is pretty much what Lutris does. I'm using it with already downloaded GOG installers, and Lutris' crowd-sourced install scripts. It looks like they do account integration, so it might be possible to directly download and install games.
It can run things with regular wine or proton installed by steam. There is a lot of complexity compared to Steam or the GOG client.
It can run things with regular wine or proton installed by steam. There is a lot of complexity compared to Steam or the GOG client.