I am a long time Linux user. No longer supporting Linux natively is a huge disappointment. But I am all for it if Proton is properly supported and exceeds the quality of the port, which is currently doesn't.

I have lost a lot of progress by enabling Steam play (which is tracked on the FBI files). This doesn't scream proper testing to me, like promised in the update where native Linux support got axed.

There is also another smaller issue I got with tabbing out of the game, it just minimizes weirdly instead of staying full screen like the native port did, which I find very annoying.
I have attached an image[files.famfo.xyz] how the window looks after tabbing out and back in (yes, the red marked window is payday).