I think there are Nobel prizes for more work here. We know so little about how bacteria affects our bodies and the true roles that they place, despite there being billions and billions of them.
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.