I just would like to address this from Steam/Valve Proton description
Q: I’m a developer; my game got whitelisted in Steam Play; does this mean I have to support an additional platform?
No; if a game was whitelisted as a result of our testing, we’ve assessed the experience to be identical (save for an expected moderate performance impact). Users playing through Steam Play experiencing Linux-specific issues should be directed to Steam for support. Keep in mind users were most likely already playing your game using Wine; you just have better visibility into it now.