Don't know where your drone is, don't know how to fly it home?
No map needed.
Learn to use the radar display.
Switch it on ...
It shows you the drone is out there in the distance.
Rotate the drone until the drone icon is pointing to home.
Then...
Have you tried getting closer?
It's not that the drone's defective.
It's physics.
The array of tiny pixels on the drone's sensor and the textured surfaces are interfering with each other.
A sensor with larger pixels (as you've found with the...
Do it indoors, if the roof and walls block GPS.
Under a sheet of metal or with aluminium foil covering the drone body.
You might need to also prevent your phone from getting GPS reception too.