PAYDAY 2 came to Linux officially back in 2016 but as of today they've removed support for it, so it will no longer see updates on the Native Linux version.
It does, however, still work quite well with the Windows version via Steam Play Proton on desktop Linux and is Steam Deck Verified against the Windows version in Proton. So while it's a loss of support for their Native build, it's still fully playable on Linux.
At the end of day, games are just proprietary binary blobs so them being native or not doesn't make a huge difference.
Lets be honest, native Linux game used to be second class citizen anyway even when officially supported, at least Proton does a really good job running those Windows games.
Same, unfortunately. Out of the last 10 native games I've played, I probably ended up forcing Proton on 7 or 8 of them. I've seen a couple developers stop porting to Linux natively to instead "officially" support Proton, and I just can't be mad about that because it's less work for them and a better experience for us.