Your personal bias against Flatpak is irrelevant to the lie that no stable development target exists.
It exists. That's a fact, whether you like it or not doesn't matter.
Linux doesn’t have a stable target to develop against
That's an often repeated lie. https://docs.flatpak.org/en/latest/available-runtimes.html
Clarification: He drew a CAD model for the rule boxes where the actual bodywork has to be in. The result is not a proper F1 26 car but something that looks like a lego model. This is the foundation for upcoming videos.
I don’t even know where to begin troubleshooting it.
Not really your task, though. You are a paying customer and the developer needs to accommodate you, not the other way around. Easiest way should be that the developer provides a Flatpak version.
In a larger sense, I think supporting them would be supporting gaming on Linux as a whole.
Bottles and similar projects don't develop the underlying technology, though. That's Wine. Bottles is a front-end with a bunch of support scripts.
Why not just use the Linux version directly?
I don't know how much of the 3 million installs I represent but I installed it, found the whole process to create a bottle an unnecessary hurdle and didn't see any functional benefits over the five or so alternatives that also aim to make Windows software compatible with Linux. The Gnome headerbar UI also is alien on both game and desktop modes of SteamOS.
So I uninstalled it.
Probably supporting Linux and open source is now evil or so.
Yeah, it sucks for the people who lose jobs. OTOH after the ABK takeover, Microsoft was suddenly by far the biggest games publisher and no regulatory body had any problems with it. Now Microsoft's own incompetence is taking care of that.
That's why future ChromeOS won't be a dedicated OS with an Android running in a VM. They'll be actual Android.