Okay, it’s nice of you that you took the time to do that.
Also I just tested my phone for the freeze bug and sadly it happens with “lineage-16.0-20190819-microG-FP2.zip” as well, i.e. I open Telegram, go into some room, post a bunch of gifs and after 30 seconds it freezes. But at least with lineage I can still close the App. Fairphone 2 OS made me reboot the whole thing by pressing the power button for 10-15 seconds.
And I also verified that this bug does not happen with my old Yotaphone 2 (Android 4.3).
So, I guess now that I actually did everything you advised me to do, except for disassembling it, that means now is the time for contacting official support and getting the thing repaired.
On an btw: Today I received a new update for the Fairphone OS, too, and after I installed it I could no longer connect to my W-LAN. And the freeze bug was still there, too.
But thanks for all your time! You’ve been a great help!