I was diagnosed with MC early 2021 as well. Change of diet is not an option, it is a necessity. While your lower G.I. tract is healing, it cannot handle the foods that irritate it. Irritating foods must be eliminated and then can be very slowly re-introduced in the months following relief of symptoms.

Here is an oversimplification of what needs to happen to relieve your symptoms and eliminate the MC:

VEGGIES- greens: NO RAW, only fully cooked. Potatoes and puréed squashes are OK No tomatoes or onions.
FRUITS - you may eat bananas, applesauce or applesauce pouches that contain other cooked fruits, then you may slowly re-introduce melons. No citrus fruits! Avocados are ok!!
MEATS - Low fat, no spices, broiled or baked only
GRAINS - Cream of wheat, oatmeal, lower fiber cereals, pasta or white breads are OK. Higher fiber breads or greens may be introduced once symptoms have disappeared. Plane crackers, saltines, plain goldfish, Parmesan or cheddar goldfish, Cheez-Its, animal crackers, etc are OK.
NO DAIRY PERIOD. You may drink almond or oat milk. As for cheese, yogurt, etc., there are plenty of no dairy alternatives.
COFFEE, TEA, HOT drinks: The best bets are decaffeinated tea OR a latte with dairy free alternative milk and decaffeinated

NO-NOs:
NO SPICES,
NO EXTRA FATS or FRIED FOODS
NO ACIDIC FOODS
NO ALCOHOL
NO SELTZER WATER or CARBONATED DRINKS
NO CHOCOLATE
NO COFFEE, even decaf
😞

I did use grated Parmesan cheese and cinnamon/nutmeg for spices, I completely cut out garlic, onions and most of the other spices that I love. I slowly re-introduced everything and have been mostly symptom free since June.

Basically you have to eat bland, easy to digest Foods for a few months. My normal diet is high in uncooked greens, fibers, nuts, dark chocolate, and of course dark red wine at least once a week! So it was extremely hard for me to do this but eliminating the MC was worth the work. also keep in mind that long-term irritation of your G.I. tract can cause other diseases and potentially lead to cancer as well.

My A1C rose significantly because of this but now it is back on the way down.

If you are interested, I am happy to provide you with information regarding my experience and that I had as well as two others with the same diagnosis.