@ryo @digdeeper @udon
Hmm. I never had hardware problems with PinePhone except the SIM card slot where the pins are easy to snag and bend. Got lucky that it didn't snap.

Easiest phone to unlock would be HTC, but there is a catch.
You must create a HTC dev account and use their online service to grab the OEM token from you phone to upload it and then receive a unlock key.
Even with this easy process and HTC kernel source code, there isn't much interest to support custom Android for HTC.
I don't know if HTC still makes phones still.