On my pixel 3a I am able to use GPS, although it is slow to connect. It is my understanding that only gps hardware is used, so it does not get the "head start" provided by approximate location from cell tower settings.
-Set "lock when idle" to "never" from system settings/ battery. (I think GPS is shut down when locked)
-Run "sensor status" app from Open Store
-Select GPS, mine shows "found supported backend", and "active"
-wait until you get a location. This could be several (10?) minutes, although mine is usually faster.
-Try your map software
Once you verify functionality, you can probably skip a lot of this.