We do have one. I guess not many people even here know about it since it doesn't have a multi-million ad campaign around it. I've been messing around with a few distros on my Pinephone. The base Pinephone is much too weak to be used as a daily driver, but maybe the Pro is better. There are distros like Ubuntu Touch and Arch Linux Mobile. There are specific phone DEs like Phosh and (KDE) Plasma Mobile. Hardware compatibility is low, but you can at least check them out in a VM on your desktop. The best part is that you can run any software that works on ARM desktop Linux, so "app" compatibility isn't even a worry. Whether the software is usable in that form factor and resolution is another factor though.
> The base Pinephone is much too weak to be used as a daily driver, but maybe the Pro is better.
Both Librem 5 and PinePhone Pro are much faster than the original PinePhone, although PinePhone Pro is still relatively immature when it comes to software support.
https://wiki.pine64.org/index.php?title=PinePhone_Software_R...