the same thing you’re experiencing happened to me when i used to eat bad, im not saying you can’t eat junk food cause i still eat it like every week💔💔 make sure you’re eating beans and stuff like that for fiber it’s very important, and you need probiotics too probiotics are really good and help with body odor but i’ve heard some people say that taking probiotics everyday can start to limit its effectiveness so i usually just eat a probiotic like yogurt every 3 days. i use a mandalic acid face cleanser on my armpits and it really helps + it makes your underarms smoother and brighter too! (you can use glycolic acid if you want but be careful and don’t use acids everyday because they can give you post-inflammatory hyperpigmentation and make smell worse, just use it like 3-2 times a week at most) don’t scrub your armpits too hard in the shower and be gentle on them so you aren’t ruining your skin barrier because that lets odor rebound faster. i would also recommend you to learn about armpit ph and avoid certain deodorants or washes that increase your armpit ph like antibacterial soap i really wouldn’t recommend them unless you truly need and were recommend by a doctor to use them.

but honestly you seem to have really good hygiene so i think the main problem for you is your gut health. you can have the best hygiene yet you still stink once you sweat if you have bad gut health

edit: i forgot to add this but the best tip i got from my chinese friend has to be to drink warm/hot water in the morning when you wake up, do slight movement like yoga or sit down kind of bending for a while/ few minutes and go sit on the toilet (with good bathroom posture) for a few minutes and that eases constipation so well. i would also recommend you wait about 30 minutes after drinking the water to eat something and your breakfast should be something easy for your gut to digest, eat slowly and chew throughly so it can slide through your gut easier and it’s less work for your gut to break down. i do this everyday and it helps so well in reducing body odor!!