I used Ensure Plus chocolate with no added fiber. Regular Ensure in the cans has some prebiotic added fiber which was tough on me

EEN is a well-described and effective therapy for Crohn's. Used less in adults, and much less common in North America for whatever reason (awareness is probably kinda low). The trials establishing it happened back in the 1980s IIRC.

Decreasing microbes is posited as one of the possible mechanisms of action IIRC. See the CD-TREAT diet https://pubmed.ncbi.nlm.nih.gov/30550821/