I think you're discounting just how much they've invested and continue to invest in Proton/WINE
I'm not really sure I am... Do we have some actual numbers into how much money they've sunk in linux?
Gaming on linux is a huge community effort, whether it's wine, dxvk, vkd3d, mesa, linux itself... and plenty of smaller projects like lutris, bottles, UMU... And all this spans literal decades, far before valve ever got involved.
Yeah each distribution has their own patch set. If you really want to compare you need to start with the most popular, ubuntu and fedora.
The two examples you gave are definitely not most users. I'd be surprised if it were even 20%. And the tray icon isn't necessary for either of them to work correctly. Most people use the computer to open the browser.