The problem is that phone hardware is incredibly non-standard. Every model requires custom tweaks and regular bug fixes, which is why there aren't many phones with good Linux support or with enduring LineageOS support or any other specialty OS. Every manufacturer does their own thing and edits Android to fit their hardware, but they generally don't release the custom drivers or any documentation. The same phone model from a different year or different region might have a different chipset in it. Keeping up with it is basically impossible, by the time an aftermarket developer gets their custom OS build running properly the phone is obsolete.
On the other hand, if a project can pick the hardware platform for themselves then everything is more manageable.
I keep thinking if they could make a phone that you just assemble like a computer and can change the parts to upgrade. I don't care it would be bit bulky. But I assume they wouldn't make as much money if people won't buy entire new phones every two years.
I propose that we delete the actual phone app. There's no rhyme or reason to actually have a stupid phone number that nobody can remember. Simply replace it with a fediverse name handle and let's move forward with the rest of our lives.
Secondly, I propose encrypted communication where I will allow o only a select few people to actually call me. If anyone else wants to call me, you can register in my phone access app and I will approve it for next call.