I remember being somewhat sold on this story by the PinePhone, but it seems like it might not be possible to buy one new nowadays.

Having just looked up the PinePhone again for the first time in a while, it does look like the Ubuntu Touch project is still alive and kicking, and compatible with some modern commercially available phones!

The main thing preventing me from having a non-standard Android phone/distribution as a daily driver is access to mobile banking apps - I'm yet to check for myself but as I understand, having an unlocked bootloader means that banking apps will consider the device "compromised" and will not work.