A notable mention is https://ubports.com/en/ which is different from postmarketos in a sense that ubports uses old kernels with heavy patches. That means: good support for things, but difficult future.
PostmarketOS uses the newest kernels and tries to integrate their patches into mainline kernel, so that the reliability is maintained with all kernel developers.
So does pc hardware but Linux can breathe new life into even an old PC since the bloat does grow at the same rate as the hardware unlike other OSes
New PC hardware is mostly compatible with the old stuff or at least somewhat standardized except at the lowest end. Phone stuff is much worse about that. Idk what a Linux phone would mean anyway.