Another alternative to mapy.com you could try is Here WeGo. I prefer it to any other Google Maps alternative I have tried. And there are some things, like the car navigation, that I prefer on it over Google Maps. I don't find their privacy policy creepy, and the most creepy parts are opt-in and the toggle clearly explains what you'd be opting into and what feature you are missing out on by not opting in. Mapy's privacy policy is less creepy than Here's in some aspects, but some of the creepiness that's opt-in in Here, like location data sharing for traffic, it's on with no opting-out on Mapy.

I'd prefer an open-source alternative, but as you said, there isn't any that currently fits my needs.