Here's an AS deep dive by Dr. Vyvyane Loh. For anyone who hasn't listened to Dr. Loh, I believe she's extremely knowledgeable in all things lifestyle and, to me, is one of the more conscientious physicians who stays abreast of current research and is able to convey it to her patients and podcast/youtube listeners:

https://www.youtube.com/watch?v=KOz1gXsuHio

I agree that when we encounter the gut microbiome, it's very hard to evaluate. Her way of addressing this topic is both detailed, fair, realistic, and at times, humorous. Check out more of her podcasts when you have the time.