I am new to this forum but pretty active on the BraX forum. They put an open source Android phone out last year that they did get ported to Ubuntu Touch late last year. I installed the 0.9 version of your software by flashing using fastboot back in January of this year.
The instructions are here:
The installation files are now here:
https://download.os-source.co/brax3/ubuntutouchos/beta/0.9/
I saw by doing a search here the the BraX3 maintainer named Plamen contacted developers to get the port started last year:
https://forums.ubports.com/topic/10999/brax3-port-still-in-progress?_=1781296139077
I love the software but it still needs work to get it to release status. There are hardware problems. Most of the time the Sim card is not recognized and when it is, phone calls can not be made in the USA. The fingerprint sensor and camera also do not work.
Is there someone here that is able to work on this?