Drone stability where GPS signals are drifting


I think that indoors (where there is absolutely no GPS), the flight algorithm will automatically do not use GPS data.
However, how is flying the ANAFI AI when there is GPS signal but with low quality while there is good optical flow data (flight is between 1 and 2m height)?
Is it possible that it drifts from something like 1 meter due to GPS drifting?
Or does the Data fusion algorithm will give somehow priority to the optical flow?

Is there a way to disable completely the GPS data so that flight algorithms do not use it?

Best regards,