kind of weird to me that we still have so few phones that have started running mainline. there's a lot of postmarketOS phones, but my understanding is they Helium/libhybris which mixes in a ton of the Android support infrastructure/drivers to do the job. i could be overly concerned, but there being so few distributions & such specific distributions targeting phones is exactly the good this work OUGHT to be unlocking, & it just seems like progress in making that happen is disorganized / not really happening, alas alas alas.
getting a toe-hold in, where we start to see self-determinism on what our devices run, would be such a compelling & powerful vision. i really hope we can start to see that!
ubuntu touch targets the Pixel3. i'd be curious to know what they did. PinePhone & Purism really took it from the top, have their own hardware that starts in a more easy-to-work with set up. but I don't see why that would be required to get a decent regular linux distro (arch, debian) running on a phone, with a gui (sans many device drivers!).