For me it depends on which one. I installed a game yesterday which used the old launcher (uPlay). Whatever I did, no matter which version of Proton, the launcher would not connect to the internet. It offered me offline mode, but because it hadn’t yet connected once, that’s useless.

The solution is a bit strange. I went into the prefix of this game and overwrote the ubi launcher folder with one from a prefix on a different game – crucially this one is a later version (Ubisoft Connect), even though the launcher folders have the same name. I let it overwrite any files with the same name.

Started the trouble game again, and Ubisoft Connect (the new version) came up. No issues connecting to the internet. Was able to play without issue.