The goal is to be distro-agnostic, but I find that Flatpak and Snap both add more bloat than is worth it. Either just use distro packages, or, if you really want cross-platform, get an AppImage and be done with it.
While that's in theory, reality is much more harsh. Treble implementations vary greatly between OEMs. For example, Samsung phones don't have mobile data working because of proprietary RIL used by Samsung. Also, Treble compatibility often breaks on newer versions of Android, especially for Pixels (which is quite ironic). Treble is really meant to make the job easier for OEMs and ROM devs to continue supporting a device. The GSI is really meant as a way to certify Treble.
I really like the idea of Étoilé, but a lot of the docs are outdated because of the death of Gna!, and right now the focus is more on the CoreObject framework rather than the UI.
> That's less of macOS itself and more how it fares on Intel hardware.
It seems fair to expect it to work well on the hardware it was sold on though. I've had the same experience as joked about above on Mac's running the OS that came bundled with the machine.
Plus, both Corellium and Asahi Linux are porting Linux to the M1 MacBooks. I have Ubuntu installed in a separate partition and boot into it occasionally. The main issues right now are audio and graphics support.