Hello, I am looking for the optimum phone to install Ubuntutouch on, and I particularly want optimum battery life and, of course, a great camera. Which phone would you recommend I am looking at Xiaomi Poco x3 or M3 otherwise they are big for me. I currently have a Pixel 6 and Grapheneos but I would like a Linux UT in the past I also had Xperia 10 and Sailfish os. What would you recommend for everyday use with a good camera?
The Pixel 3a? As stated on https://devices.ubuntu-touch.io/ it's the best port out there (and my previous experience with a OG Volla/GS 290 confirms this). Now is Ubuntu Touch perfect? No, and everything depends on your use-case (and because of no VoLTE support, the region you are in also matters). You can also try Droidian (https://droidian.org/) with a Pixel 3a, so given likely availability of a working, used device for less than USD/EUR 100 you can't go wrong with it, IMHO.
I got a 3a and put UT on it but couldn't make mobile data work on a UK sim. It was the same for Droidian unfortunately. Droidian looked especially cool.