I have a "braveheart" pinephone (one of the first ones) and I just use it to play around with it's features, do distrohopping etc.)
Most of the time i used an arch build with phosh. But actually I highly recommend postmarketOS, the installer is straight forward and let you build whatever you want. Actually I run postmarketOS edge with encrypted f2fs and gnome-mobile on it. gnome-mobile works better on newer phones but it is still usable.
I prefer my grapheneOS phone because it is faster has more apps, apps are scaled correctly etc. Not too much battery drain...
PS. I managed to run Thunderbird usable on pinephone, I just play around with the look&feel and now I simply have just the mail cards and I am able to interact with it without too much scaling issues.
I think Linux phones needs more time. My dream would be a phone I can plug into a docking station and work on where I stopped. Most platforms gave this dream up. But Linux is on it's way to do it. It's actually possible, thx to gtk4, libadwaita etc.
What is the current state of Gnome mobile? I thought that it wasn't finished yet. Is it as good as Phosh?
PS. I managed to run Thunderbird usable on pinephone, I just play around with the look&feel and now I simply have just the mail cards and I am able to interact with it without too much scaling issues.
Phosh comes with Geary. I haven't used it, but it looks like it should work well on mobile.
Phosh is definitely more polished and an attempt to make gtk mobile friendly. I actually prefer gnome-mobile for testing purposes. It's exactly like gnome-desktop and apps are opened each in an workspace, which is an impressive solution. It also needs more resources, and its not recommended for the first pinephone.
I know about Geary. But it's not the same as a complete Thunderbird install. There I can use my smime/openpgp certs and tags are also synchronised.