I think this is a problem that can never be solved - the release of new phones annually and the ability of a small company like Jolla to keep up with this pace before those phones become difficult to obtain new is something that has been going on for years.
Furthermore, this approach also inevitably results in ‘never quite finished’ adaptations - for example the Xperia 10 iii phone (the latest in the Xperia line to be anything other than early access) is now a near 4 year old phone, originally released in 2021, which continues to suffer from basic issues like loss of sound, disappearing fingerprint unlocking, mobile network access from Android apps, memory management issues (OOM killer), and so on.
Sadly, in my opinion, the most recent properly reliable adaptation in my opinion is the Sony XA2, but that’s now a seven year old phone and now unusable in many geographies (no VoLTE support).
I think the Jolla C2 was perhaps a way to break this cycle, but the adaptation on this device doesn’t appear to be any better than what came before, and nobody knows how long Reeder will go on producing the hardware. Even if Reeder do keep producing it it will quickly become outdated (some have already said that it is outdated now).
So, how to break this vicious circle?