I’m in the same kind of situation, what functional medicine, diet and lifestyle changes did you try? What worked?
There are a ton of rabbit holes you can go down for SIBO, leaky gut, gastroparesis, MMC, etc. All of them revolve around how fast and how well food transits your gut. Longer food stays inside you, the more problems you have.
From my experience, there's nothing you can really do to fix this beyond 'live a normal healthy life, and let it heal itself, slowly, and not fully.'
I worked at a hospital (in IT) during covid, had to be onsite a couple of days a week. lots of people dying all around, n95 all day, etc. not a problem. As I settled in, I realized my manager, and the director, were absolutely toxic people on a powertrip. they didn't care if you said "this is likely to bring down random hospital applications, we need to do it this other way." 2 stars on glassdoor, cowboy hats all around, staff morale not present. they'd come up with technical ideas on how to do something, despite being barely technical people. telling them how to do, say a data migration online, because you're an SME who's been doing it for almost 30 years is a personal challenge, and you get crapped on, overruled, and put in your place. Lots of downtime, lots of patients affected, yet they report literal fake status reports up the chain and generalize-away every issue to the point that the generic statement hides the issue.
I started getting heartburn during the day. Then I started getting hearburn in the morning as my alarm rang. Then I started waking up 5min before the alarm rang, with heartburn, and teenager zits on my face at mid-life. Morning was now a cup of baking soda water instead of coffee. ion pump blockers. more baking soda.
after 6 months, the manager ordered me to execute a migration plan that would shave off 2 days from a year-long plan. I made a nice writeup stating we need to monitor sockets on the array a few days to make sure people aren't actively using the data she want's to trash. Last time she had me do this, she asked over email, and it brought down a whole clinic that was using a share she thought was unused. This time, I was asked not over email, but with a call from her cell phone, to my cell phone.
I said no problem, send me an email or type it in chat, and I'll do it despite the high risk. I was of course fired 5 days later, but already had a new fully remote job, which I started 5 days earlier (lol).
The point of the story is - the stomach issue didn't go away. 3 years later, it's still there. It's much less, but that last/final bit, where a couple of times a year I need ion blockers for 2 weeks, and maybe one day a week I still need to start w/ baking soda water - that's probably there to stay. I eat very healty, lots of fiber, I'm fit. That 6 months of acidic people did damage that a middle-aged body can't heal all the way.
There's nothing you can do. This is your new thing now, have fun with your new friend. And watch this: https://www.dailymotion.com/video/x6xc3r7
And best of luck, I suspect you really helped some patients at your former job relative to someone who would have been less conscientious. Maybe even me, we’ll never know!