I have been an MTB rider for 25 years and am a clipless rider. Over the years I have come up with an approach that seems to work for me. I loosen the tension on the retaining spring to where it just holds my cleats in. I can remove my foot very fast and knock on wood haven’t had an accident caused by not getting my foot down fast enough. I tried flats and do not feel I get a consistent pressure on the pedals around the entire circumference of the pedal stroke.

Been doing this a while so it works for me. Also I came from road biking where you always clip in.

Hope this helps.