I have not seen any love for the Cosmo's mobile linux hardware. It has much better specs than the Pine and Librem offerings, has a headphone jack unlike the Fairphone 4, and seems criminally unmentioned.
https://store.planetcom.co.uk/products/gemini-pda-1
https://store.planetcom.co.uk/products/cosmo-communicator
Older Android devices supported by PostMarketOS are also never mentioned, such as these Xiaomi devices, with better specs and will be better devices for general usage, I see GNU/Linux on Android as the natural response to my generally seen Linux usage (longevity of hardware and software support for devices you already own, rather than buying new hardware to run linux).
https://wiki.postmarketos.org/wiki/Devices
https://wiki.postmarketos.org/wiki/Xiaomi_Poco_F1_(xiaomi-beryllium)
https://wiki.postmarketos.org/wiki/Xiaomi_Redmi_2_(xiaomi-wt88047)
I've used Ubuntu Touch with supported devices through Hallium ase well. If any of your old devices support these or you want to talk about other Linux mobile hardware, please do, I think there is too much bias and assumptions that only those 2 are "Linux phones".
https://devices.ubuntu-touch.io/
And the installation process was so easy. No fiddling around "rooting" a phone - just "pmbootstrap init" and answer a few questions.
I've not actually used it as a phone yet, so for me so far the usefullness is limited, but I read it works, and I can write graphics to the framebuffer. Of my own phone! How cool is that!
It also boots into a variety of desktops in various states of usability.