I don’t have the capacity to reply right as much as I’d like now, but I would like to signal my intense sympathy with the premise of this thread.
It’s more heavyweight but I don’t think anyone mentioned virtual machines as an escape hatch - though steam-run (as mentioned) might be entirely encompass that? (just entirely sidestep the whole issue)
sidenote: on the note of VMs, I believe there is work being done on some wayland stuff that might make guest windows usable as host windows, which might be kind of interesting.