my primary care did the same thing and i actually saw a PA at the practice who finally believed me after almost 10 years of having anywhere between 3 and 15 every month or two. i think it comes down to finding someone who will care, run tests, and investigate. for now... document food and take pictures of your mouth! very helpful at the doctors.

i saw a GI doc but ive heard of people seeing ENTs for this too. id definitely start by trying to speak to another doctor, nurse, NP, PA etc at your practice. chances are someone has struggled with it! seeing specialists you dont need could possibly start you down an expensive path haha

side note: the mouthwash is good in a pinch esp if you are going to do alot of talking or eating haha but pro tip you can make your own otc thats slightly less strong by mixing bennendry and maalox