Map view and built-in gps gone

Suddenly on a ride the map was gone. I was essentially doing breadcrumb navigation. Only a grey background.

I found help articles recommending to turn on "location" in settings. But I could not find "location". Strangely the built-in gps in the sensors app is gone, too. However, the GPS was obviously working, I was recording the ride and all data fields worked. I tried deleting all sensors and reinstalled them, but no avail.

Meanwhile, after my ride I can see the map again, but not the built-in gps. I played around a bit and have no idea why the map is back.