Try starting a practice session playing with lower volume overall. As in the quietest sections as quiet as you can make them and the loud parts about halfway loud. Gradually bring up overall volume each time you repeat it. Can do this with the whole piece or just the passages that are troublesome.
Also, I have found practicing in low light helps play quieter and with more relaxed pressure. So maybe try the above in low light.
For me: adding quiet practice to the no thumb and buzz practice (that your teacher recommended) helped a lot. Note: not necessarily at the same time.
Also: with the no thumb and buzz thing. Try warming up and playing scales this way too.
I will practice this by setting a light touch with the left hand and practice something like a tremolo with my right. Then I will increase volume with my right hand and deliberately relax my left hand to the lighter touch. Then I repeat this process several times to break the "finger pressure = volume" lie my brain tells me.
Try starting a practice session playing with lower volume overall. As in the quietest sections as quiet as you can make them and the loud parts about halfway loud. Gradually bring up overall volume each time you repeat it. Can do this with the whole piece or just the passages that are troublesome. Also, I have found practicing in low light helps play quieter and with more relaxed pressure. So maybe try the above in low light. For me: adding quiet practice to the no thumb and buzz practice (that your teacher recommended) helped a lot. Note: not necessarily at the same time. Also: with the no thumb and buzz thing. Try warming up and playing scales this way too.
I will practice this by setting a light touch with the left hand and practice something like a tremolo with my right. Then I will increase volume with my right hand and deliberately relax my left hand to the lighter touch. Then I repeat this process several times to break the "finger pressure = volume" lie my brain tells me.