Thanks for the link.
According to Google Play, AutoMate is not compatible with my S21 Ultra on Android 14. Plus, as you said, not updated since 2021.
Apparently for Android 9.0 onwards, Google Assistant has a Driving mode that works once you load Google Maps (portrait mode only, limited countries includes UK).
Enter (or ask Google Assistant for) a destination and Start navigating.
Then Driving Assistant detects that you're moving, and allows you to handle calls, music (from a streaming service), directions, all handsfree like Android Auto. Clearly the phone needs to be in a holder. Not sure if it works via a headset (it should).
EDIT - just found
AutoZen-Car Looks like a similar thing, maybe a bit Beta but people like it and developer actually responds to people!