I’m pretty sure if we aren’t careful the same replication crisis that happened in social science will happen here, the interaction of the gut bacteria is so complex it will be very difficult to get consistent results.
I'm guessing we're 0.0000001% of the way there, given how complex all the interactions must be.
This is a chemical (?) simulator that's been around since 1993 I believe: https://www.wur.nl/en/product/Simulator-of-Human-Intestinal-...
I also found this numeric simulator: https://learn.genetics.utah.edu/content/microbiome/simulator... but I can't view the content right now.