So, after following the discussions for quite a while, I decided to pull it off.

Having gone though the support list of various distributions, I chose Pixel 3a for my setup. Among the dirt cheap smartphones, it seems to enjoy the support of almost everything.

I decided to install PostmarketOS with Plasma Mobile. In the meanwhile, I also tested Mobian (didn't work for me for some reason) and Gnome (I ended up being too much of a KDE fanboy).

The overall experience is, honestly, mixed. It sure is exciting, and I've spent a whole day tinkering here and there (and feeling a bit nostalgic for the day I felt this way about Linux as a whole), the hardware support was a pleasant surprise, up to multipoint Bluetooth TWS headphones, but still, system stability isn't anywhere near a daily driver, and software support lags behind in many ways.

In any case, now I too have a platform to look into the future. Year of Linux mobile, anyone? :)

P.S. Any advice on censorship-resistant (VLESS/Reality/AmneziaWG-based) VPNs for PostmarketOS on ARM devices?