Choose whatever is best for you.

That being said, as a Linux user I always appreciate a native Linux version of a game that runs well and is updated promptly.

As far as I know, there are game engines that make it easier to publish on many platforms, but I'm no expert.

The days/weeks/months it would take me to add it and fix all the probable bugs it entails could be used to improve the game itself

Making a game multi-platform is improving the game. Massively.

The high level of skill required to write multi-platform games is why most studios don't bother: Windows developers are a dime a dozen but skilled multi-platform developers are rare. Have you got what it takes? Do you have the cojones to step up your programming game? Or are you happy to wallow in the slop with the rest of the Windows game developers?

Also, remember that Linux isn't the only POSIX OS. If you do your porting right, you get to support a shed load of other OSes for very little.

At this point, Linux native is almost more like reinventing the wheel. The people working on the compatibility layers have done so much work to make a windows game feel native that you can almost think of them as cross compilers in a weird gross way

if a bug arises from using proton, it would cause the same issue for users that are forced to use proton.

just click the button that builds for linux. build for as many platforms as you can. if you cant fix all of the bugs due to time, then you'll become a better programmer for your next game and not make thise same mistakes <3

I think the only big benefits that come from having a native Linux port is performance, and compatability (in case running through wine / proton didn't work.) Other than that I can't think of anything else.