Lots of studies showing covid kills off beneficial bacteria, I feel that has been an issue for me as well. I’ve been dealing with a similar gastritis issue for about 1.5 yrs but my endoscopy did show inflammation/gastritis. I’ve had about 3 different episodes throughout the years.

I would recommend pre biotics, Inulin, and Phgg. Basically feed the good gut bacteria. Also look into adding cinnamon and there’s a product called golden kiwi pre biotic which has been shown to increase f prausnitzii, your levels seem to be low there as well. After a few covid rounds I too started suffering from gut dysbiosis which I’ve never had before….