Thank you for sharing that beautiful story about your daughter. There's been research between ADHD itself and profiles of microbiome organisms that are unusual, but I'm unaware of studies looking at the impact of stimulants or other ADHD medications on the gut microbiome.

This is s a few years old, but here's my video on the ADHD/microbiome connection:

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