On mine I run PMOS configured nearly the same way I have my other computers configured (same WM and everything.)
So I would say maybe in a year or so Debian testing could run on it.
It’s running already (well as close as possible for mobile). But they say «in a year» it’ll be usable as a daily driver too.
Mobian and Manjaro ARM are much more lenient about patching up their kernels in the name of device support (perhaps to a fault, but if the images work...).
I would call it....sort of official? It isn't Debian per se, but many of the devs working on it also are working with Debian to get as much upstreamed as possible (or are affiliated with Debian proper). It also tries to use upstream Debian packages as much as possible.
I run that (and develop for it!), and I have ssh on it.