Post-stress inflammation can persist due to latent infections of various kinds. To accelerated recovery, I would recommend a course of plant-based anti-pathogen treatments. (Not going to shill a specific one.)

My non-verbal son has autism and gastrointestinal issues. Unfortunately, all the pediatricians would test for is C-diff. After years of problems expressed in the most challenging behavioral ways(!), we finally had an MD (trained as a naturopath) prescribe a battery of pathogen tests (https://www.gdx.net/gut-health) that identified an obscure protozoa. Nearly, overnight difference upon treatment (a drug). The remaining GI issues were addressed with plant-based treatment. I've also suffered from GI issues that improved substantially with anti-fungal focused supplements (e.g., French Tarragon leaf).

I would recommend eating a diverse range of fermented food too (yogurt, real sauerkraut, etc), since they compete with pathogens for resources.