Only Steam. You can get non-steam Windows games running using Proton too. I had trouble getting Ubisoft (AC Valhalla in particular) working with Lutris and Wine, but it was super easy with Steam using the “add non-steam game” option and trying different Proton versions till one worked (might’ve had to use a GloriousEggroll version, don’t remember).
Only Steam. You can get non-steam Windows games running using Proton too. I had trouble getting Ubisoft (AC Valhalla in particular) working with Lutris and Wine, but it was super easy with Steam using the “add non-steam game” option and trying different Proton versions till one worked (might’ve had to use a GloriousEggroll version, don’t remember).