I don't know, Google integrated the mainline Linux kernel a while ago. Probably most of the modern ones.
PostmarketOS fills the plaything niche like the Librium 5 and pinephone do but much cheaper with much better old hardware. Aside from a checkmark of running the latest kernel and hardware switches what can the librem 5 do an Android phone can't do much better? They aren't good phones.
Lifetime updates, no proprietary drivers, support of tens of different operating systems, schematics, openPGP card, desktop apps and convergence, verifiable security.
Those are features but not descriptions of good uses. Running a small laptop or steam deck fulfills all of that and much more and I've yet to see an instance where it's a good use. Again it sounds like a plaything to tinker with, with no real world use as a phone or computer.
> Running a small laptop or steam deck fulfills all of that
Why on earth do you need two separate devices (phone and laptop), when you can use one for both use cases (phone with convergence)? No synchronization or double-backups and maintenance required. Also, decreasing the amount of e-waste is a good thing as well as fighting with the user-restricting duopoly.
It looks like for you Linux itself is also just for tinkering, since you can already do everything with Windows and MacOS, isn't it?