The Search for a Free/Open Source Mobile Operating System
Switched to GrapheneOS with the Pixel 5. 
Email/Calendar integration works fine (K-9 Mail).
Signal as instant messenger.
Organic Maps as Map application.Replaced Apple Watch with GadgetBridge and a Mi 6 band (cheaper and I have easy access to all data, you need to sync once with their app after you get the key you can delete it ... did the setup on the iphone and copied out the key with a commandline python script from github).Syncthing is amazing (local sync of audio books, camera images).AntennaPod is equally amazing as a podcast client (I prefer it to overcast switching from the iPhone).Other apps I'm using regularly: AnkiDroidSo far so good, not having the Google Services seemed ok, except:
1. still in search for good camera application, recommendations welcome.
2. a replacement of Reeder as an RSS reader (so far have not found a solution that works for me).Yet, just started programming for it a bit and have to say I love flutter. It's pretty polished (and great for my needs).