Wouldn't "Compatible with Kernel 5.11" be a pretty good/accurate bar? That is if they upstream their drivers or develop their closed sourced ones against certain kernel?
I would suggest you to support exporting to OpenTimelineIO - opentimeline.io "Open Source API and interchange format for editorial time line information." Most of the softwares you mention already support it, if I am not mistaken.
Just checked, and the equivalent of Cmd+~ on GNOME is Cmd+`.
That said, I rarely use Cmd+Tab anymore, I just move the mouse to the top left corner and pick, now that screen could use some UX improvements (i.e. hotkeys for the apps, and maybe grouping, since when you have a lot of open apps, it is hard to find what you are looking for).
I agree with you mostly, but I think the OS is there (Linux) we just need more mainstream Open Hardware, and hopefully Librem 5 will be the one to push things forward.