I put PostmarketOS on a spare device recently. PostmarketOS describes itself as currently being in a state suitable for Linux enthusiasts to try out, not for wider use. That seems about right to me.
On the fun side, it's proper desktop-style Linux. I can SSH to it from my laptop. I can compile software on it. I can run programs that have no business running on a phone. On the not so fun side, the cameras barely work, data over USB doesn't work at all, and battery life is not good. Desktop Firefox on a phone screen is pretty bad. Rumor has it there's some support for Android apps, but I've been looking at Waydroid's splash screen for a long time now with no progress.