I agree. It's rather the speed than the pressure of the strokes that makes the sound louder.
Also it is a good idea to check the nail lengths. Oftentimes you need a little longer nail on your C (pinky) that is significantly shorter than IMA. If you don't have the longer c nail, then that might cause IMA to hit the strings harder, resulting in excessive pressure applied to IMA nails.
Longer P nail might also cause issues when playing abanico lasugueado, so that you might redefine your P nail shape to something that works for both classical and flamenco (or lasgueado techniques). Some are keeping longer toenails to attach to cracked finger nails, or using a piece of ping pong ball shell for the purpose. I have employed neither of those solutions, as I am lucky enough to have stronger nails.
Otherwise I can only suggest Ben Woods' nail video. Again I never had any issue with my own natural nails so that I have no experience in doing any of those cares in the video.
I hope this helps you.