Basic rule of drone flying signal stability is to maintain a clear LOS (line of sight) for an unobstructed signal. If you can't see the drone with binoculars because something is in the way (not because it is too small to see), your signal is...
See post #46 on page 3 of this thread. A Mini 5 Pro just ‘dropped out of the sky’ when the Mini 3 Pro Plus battery being used gave up under load. New drone required.