Search for medical treatments, and then look for doctors who provide them - post about underarm sweat gland removal
DISCLAIMER: I am not a doctor or medical professional of any kind, and nothing here is medical advice.
So, many people go from doctor to doctor looking for a cure. In the modern age at least, there are likely no medical treatments where there is just one magic doctor who is capable of offering them. So look online to research what medical treatments are available for this, and then seek out a doctor who can offer it. The main thing that is available is to have your underarm sweat glands removed/destroyed/shrunk. Botox is a treatment, but something called Miradry seems to be the best treatment for this at the moment.
There are serious concerns about going this route. I have read many horror stories about people with Hyperhidrosis either getting getting their sweat glands removed, or else the nerve controlling it clamped down (if my memory is correct), and getting massive compensatory sweating. So, after a few months the body finds another way to get rid of the sweat, and its usually far worse than it was before, and can't be fixed.
Miradry promises no compensatory sweating, but I have read about people getting it done for this condition, and having the sweat come out from somewhere else a few months later. I have not read about it actually being worse than it was before. If the problem really is metabolic then this is exactly what would be expected to happen. This probably happens to prevent a deadly buildup of whatever you can't metabolize properly.
Now, it might be that your condition is not metabolic, but that your apocrine sweat glands are too large, too numerous, or too active. If this is the problem than this may cure you. Normal people who go vegan and remove spices from their diet always report the smell of their sweat improves, so the fact that diet affects your symptoms does not necessarily mean you have a metabolic disorder.
My take is that due to the risks, and the fact that there is a high probability that most people do indeed have a metabolic disorder, having your underarm sweat glands medically dealt with should be the final option, before simply accepting that this can't be cured.
Now, obviously you have to have either some evidence that your underarm sweat is the culprit, or at least an absence of evidence of an alternative explanation, like the smell coming out directly through your pores. If you have a related breath issue as well, this is clear evidence of a metabolic disorder, and so removing your underarm sweat glands is likely not going to work.
I want to be VERY clear that you yourself must accept the risks that come with seeking out a medical procedure to destroy/remove/shrink your underarm sweat glands. Making the wrong decision here may have irreversible, life long consequences, and this is why I advocate for trying everything else first. Hopefully the Miradry people are correct when they that compensatory sweating is not an issue. You need to spend at least several hours reading about other people who have had this done to treat this condition online, before actually singing up for it. If you have had Miradry or something similar done, please post a reply about your results!
The other medical intervention I am aware of is a fecal microbial transplant, which I don't know much about, except that it apparently worked for some people. There is also someone working on transplanting underarm bacteria between people to treat this condition. Do a google search, and see if this is actually currently available for patients - I don't have a link or name. There are all sorts of advanced diagnostic tests like genomic sequencing and things, but I don't expect any kind of treatment path to come out of that, which is the problem.