Hi Serendipitous! Welcome Aboard! I am familiar with all of the items you question. However, I don't feel qualified to recommend a particular direction.
There are two points I would like to put out there, though, if you are open to them. One, is that virtually all of the typical symptoms for Gastritis are the same symptoms for SIBO (Small Intestinal Bacterial Overgrowth), and it is commonly misdiagnosed among the IBS and IBD population as Gastritis. So if you haven't discussed it with your doc, you may want to mention it/rule it out. There is a good breath test for it (non-invasive, no pain, Yay!). I'm not trying to complicate your life, honest! The mainstream GI community is just getting to know the clinical data on SIBO from several scholarly research hospitals in Canada, US, UK, & Australia over the past 2 years, and some hospitals/docs are just not as aware of it to date, but it's very reputable/clinically supported information.
The second point is that if you do have SIBO, the SCD will not help as much because it allows honey, and fruits (apples, pears, etc.) that actually aggravate SIBO! The foodplan for SIBO is low-FODmaps Elimination (and then systematically broaden, thankfully) Diet. There are great wiki-links on this forum. There are also many RD's, one in particular that I follow, that educate and provide recipes/books for low-FODMAPS (there's a smartphone APP for it, too! WooHoo!).
Anyway, I recognize that I tend to be a broken record on this condition to its lack of representation/recognition. Should probably change my forum name to SIBOwoman...to the Rescue! hehe
) Best wishes going forward.