I'm not sure what the solution is to get it working for you again, but I can say that setting location to GPS only does not ensure that it will actually look for your location via GPS, it just means that it will only ever log your location based on GPS. This means that, when you're out traveling somewhere and you use an app that has permissions to access GPS data, that app will enable GPS and use it (such as Google Maps), then Google will create the log of the location data while GPS was on. However, the moment an app finishes using GPS, Google is no longer logging data because you aren't using GPS anymore. This is done to save battery on the device.
If you want to test this, you could use a GPS app (like a different map software, to ensure that the location data isn't just being shared from Google Maps to your location history), ensure the app is actually turning GPS on, and then check whether Google has logged that location data at the end of the day.