Keep talking to your medical professionals, that’s the best approach. Officially/actually!
My friend who had similar recent flare-up after a move to a new uni, ‘solved’ hers (non-officially/anecdotally) by
1) using a cartridge water filter, a basic model, for drinking-water & tea etc
2) plus taking probiotic gummies (Apple Cider Vinegar Tapioca Gummies - 1000mg - with Organic Turmeric, Ginger & Probiotics - Unfiltered & Raw with the Mother - 60 Vegan Gummies~ €10) for example
and weirdest
3) taking a quarter of a real apple, small windfall apple from a real apple-tree in someone’s garden, every day or whenever possible. Eat simply, seeds, skin, warts & all. Seems to be the most fullest thing stuffed with real microbiome refreshments/boosts. Find a friend who isn’t a farmer or supermarket who has an apple tree or two, and collect all of their small apples?
[Real bio, not supermarket “bio”, so far it’s working]