I have one phone that can do that, an old Android One phone codenamed seed. With qualcomm’s MSM8916 chipset. It also runs mobile linux, and still gets support.

Are you sure, because it is listed on their supported devices list. Unless it’s the SoC that’s different.

Not since the introduction of OneUI 8. Those with older OneUI have some options, Lineage has roms for models up to S20 series I think.