Neuromodulation for the health of the vagus nerve and brain/gut axis stuff has recently become a huge area of R&D, especially since it seems to have a positive outcome on long COVID. I suggest you read in the usual medical research and study sites about this, as well as the journal Neuromodulation. I have used a transdermal ultrasound vagus nerve stimulator for over three years to aid in resolving IBS/SIBO and it has helped a great deal. I have also been on a continuous prescription of Rifaximin for this time. I have gone from not being able to eat 95% of foods to not being able to eat 15%, and from having to sleep most of the time to being able to do about half a day of productive life (I also have MCAS, POTS, hEDS, anemia, and CCI).