[shmerl]

You don't need Proton without Steam (since it has various Steam specific stuff), but yes, you can.

See here for example: https://www.gog.com/forum/general/adamhms_linux_wine_wrapper...

However, you can simply use upstream Wine with add-ons like dxvk[1] (which is used in Proton).

Using esync[2] (also utilized by Proton) requires special branch of Wine, since it's not going to be upstreamed and it's not as simple as installing dll overrides.

1. https://github.com/doitsujin/dxvk

2. https://github.com/zfigura/wine/blob/esync-rebased/README.es...