Hello. Here's a thread for all the random video game news. Previous topics included Valve's support for Linux and trailers and new coming out of Gamescom in Cologne, Germany. PAX coming up soon too, I believe.
Give it a few weeks. Right now Proton is only in the Steam Beta client and it has some issues (namely segfaulting) on some systems. I think we can expect some bumps in the road at first. Unless you want to be one of the first and provide Valve with bug reports and feedback, which is cool if you do want to do that, I wouldn't recommend it unless you're an experienced Linux user, I would wait until at least the first round of issues are worked out.
Anyway, long story short, Valve have not given up on Linux, in fact they've been directly and indirectly responsible for Linux gaming being in a better place now than it's ever been. Things continue to move forward, but these things take time and we're also talking about Valve here and we all know Valve works on Valve Time.
That's all good news. I'll give SteamOS a go since it's...free!
Also, here's a nice preview of Sekiro: Shadows Die Twice.