axl You mean like a literal vertical perpendicular line from my phone to the cosmos? That makes GPS tracking rather unusable, and I'd really rather not use Google services...
GPS works by a radio receiver in a device receiving faint signals from satellites in orbit. As with any radio signal, objects in the way reduce the signal strength. GPS works reasonably well through light cover, such as a tree canopy or a single non-metal roof, but acquiring an initial lock is harder than keeping a lock.
Googie built their enhanced location system (using Wi-Fi and cellular signals) precisely because pure GPS doesn't work all that well, especially at initial locks, especially without a clear sky view.
So right now the options are indeed using Google's system versus having reasonable GPS signal strength. As indicated, the GrapheneOS project is working on a third option.
As indicatd, the GPSTest app is a great way to evaluate GPS signal strength where you are, and progress toward a lock.