Here’s something to think about..
years ago when i first started playing the sax, there were the odd days when i played the sax, and i was making unintentional high pitched squeaking noises on some keys. The obvious approach for me was to either tighten up my embouchure or change the reed or clean the spit out of my mouthpiece – result the squeaks stopped.
That approach was ‘how to stop the squeaking’.
A couple weeks ago (light bulb) instead of doing a lot of randon things to stop the squeeking why not deliberately try to make intentional high pitched squeaks while playing, that way i should then have a better idea of what was the underlying cause, giving more control over the sax.
I then discovered a very easy was to make the mouthpiece squeak on its own, while just playing the mouthpiece..
food for thought