I want to stop using mouthpiece pressure
When I don’t use the pressure my playing is not strong.
You can NOT just stop using pressure.
You have to correct the reason that the pressure was needed first.
Then after you have a close set embouchure, good breathing habits and good muscle strength you can work on reducing pressure.
Practice LIP Buzzing. It teaches you how to form your embouchure and makes the lips stronger.
Do the pencil exercise for 3-4 minutes at a time. (Most pressure players can barely do a minute.) This builds muscle and shows you how to contract to play higher with less pressure.
Play at a whisper. This works the lip aperture to aid in pressure reduction.
Then play arpeggios using as little mpc pressure as possible to get used to both the feel and to allow the lips to LEARN how to flex and contract to produce each note. The lips must be closer with no pressure than they are with pressure.
No pressure is NOT an option. LESS pressure is.
The lips produce compression by lip against lip movement. They also can control the aperture by pulling the corners in to play high.
As a pressure player you never allowed your lips to do that so the muscles must be worked first.
Try to practice with this grip where the horn is resting on the thumb and 1 finger. Do NOT grab the valves or pinky ring.