You CAN do steep turns at 500 feet with two notches of flaps at 80 knots
Went for a flightseeing trip in Alaska, over Glacier Bay.
At one point my film ran out, whilst we were over a glacier, between two rock walls. "No problem" said the kid who was flying, "you change your film and I'll just stay here".
He proceeded to do a steep turn on the spot until I'd changed the film. But the rock walls were sufficiently close that to get the turn tight enough he had to
close the throttle somewhat, not quite how you're taught to do steep turns on the PPL course! (This was at nowhere near 500' above the ice, and nowhere near 500' from the cliffs either side.)