Sorry to hear of your problems with equalizing.
At the beginning of her career, also my wife could not equalize.
She passed through a number of specialist physicians, and was sentenced to need surgery. In the seventies this was really experimental (now it is not anymore).
As we are in Italy, visits, instrumental medical exams and surgery are completely free. So this was not the problem, but my wife (she was my girlfriend, at the time) did not like the idea of inserting a probe through here nose for reaching the inner ear.
The solution was given her by a good scuba instructor, who incidentally was also finishing his studies as MD. He did train her to use several alternative equalization methods, including Frenzel (for free diving) and Marcante-Odaglia (for scuba diving).
After learning these more powerful techniques, my girlfriend started equalizing. And dive after dive, the Eustachian tubes grew wider and more elastic. After one year the problem was completely solved, so she managed to complete her training, and a few years later she became an excellent instructor.
So, while surgery is definitely the last possibility, I second the suggestion of first attempting to employ better equalization techniques.
Frenzel is tricky to learn, Marcante-Odaglia is even more tricky (as your mouth is open, holding the mouthpiece of the regulator). It takes time and effort to learn them. But they are very powerful, I am almost sure that they will solve your problem.
Instead, I warmly discourage the use of anything blocking the water pressure to reach your external ear. You must equalize, you must not use devices which "protect" your ears...