Yes but that's not first party, voids the warranty (messing with bootloaders, yuck), in my experience has tons of problems with propietary drivers, is still Android (which is an awful OS/ecosystem for anything that isn't a phone), eventually stops being updated (as many of my not-so-old phones can attest)...

RPi and Android phones might overlap for some applications but I see them as very distinct devices.

> Any Android phone can be rooted and flashed to Lineage os atleast.

If your manufacturer hasn't decided to lock the bootloader, that is.