There are phones that do run things like postmarketOS which aims to maximize as much mainline linux as possible. Some well-supported devices are pretty cheap on

There are phones that do run things like postmarketOS which aims to maximize as much mainline linux as possible. Some well-supported devices are pretty cheap on the secondary market, and for this use-case, things like broken screen etc do not matter in the least. You'd still have binary blobs of HAL for some peripherals but that's not different from raspberry pi.