Wouldn’t unlocking the bootloader and installing a custom ROM be easier, more stable and cheaper than buying a niche product that’s unlikely to work properly?

What exactly are you looking for? Android IS Linux, do you want to try a different “distribution” just for fun?

The latest pixel devices (since 6 I think?) already provide accees to a /dev/kvm device, so maybe you could even run a normal Ubuntu server VM on your phone for hosting these services.