an AOSP (Android Open Source Project) phone already is a Linux phone

Until it has ssh access and a command line package manager ala Debian APT, RedHat YUM, Arch Pacman, Alpine APK... it's not "Linux" enough for me.

No: PMS doesn't count. Compared to ssh -> shell, ADB is a PITA. If ssh is too much attack surface for you, securely switch it off until you need it.