Not OP but I like to share my experience.
I have never been entangled too much with Google, so getting away for me was more like choosing a different path from the beginning than finding my way back.
I use Posteo for my mails. It’s one Euro a month and comes with contacts and three free calendars I can sync using DAVx5. This works perfectly. I use CoMaps for navigation and a funny old TTS engine called eSpeak. It doesn’t have traffic yet, but the EU told all members to openly share all traffic information, so I’m looking forward to that. Until then, I drive without that information, which was perfectly fine until like 7 years ago. What else? Aurora Store to get a hand full of apps from the Play Store like Signal and Banking. That’s it. You just decide to live without it and do it.