/e/OS has its merits, I’m using it myself.
As long as you are aware that compatibility to Google-dependent Apps (these are not only Google’s own Apps, these are most of the popular Apps in use on Android phones) can break at any moment for any given time.
The compatibility is nice to have, but it should not be taken for granted for really essential needs, e.g. work-related, medicinal …
In practice most of the time those Apps will work just fine, else /e/OS wouldn’t have this much users, but a little awareness can’t hurt.
Worth considering if compatibility matters more …
The official partnership of Fairphone and Murena brings benefits to Fairphones for sure, but the responsibilities are clear:
Fairphone OS is the only OS supported by Fairphone on Fairphones.
/e/OS is supported by Murena themselves, and they will only support your device in hardware if you bought it from them.
If you run into trouble using /e/OS and want support from Fairphone, you will have to reinstall Fairphone OS first.
As for the planned obsolescence bit … yeah right 
. You might as well believe Fairphone just wanted to annoy you personally, makes as much sense.