I can't use GPS navigation on my Apple Watch Series 9 watchOS 11
Cause 2 of 3: There's not adequate GPS signal
The first time your Apple Watch is to find a GPS signal on a new location, it may take several minutes. Urban agglomeration or forests may interfere with the GPS signal.
Solution: Go to a place with a clear view of the sky and wait a few minutes while your phone searches for a GPS signal.