I would encourage anyone with MCS to consider brain retraining and the DNRS is excellent and very clearly presented. If the DNRS presentation didn't resonate well with you then the Guptaprogramme is the same in principle but different in flavour.
My understanding (others may differ!) is that in brain retraining I was really doing something very simple, which was to recognize the symptom, thought and behaviour patterns related to MCS and to interrupt them by flooding my mind and body with either a joyous ,peaceful, happy, humorous, or even bitter-sweet emotion, just for a short period to weaken the oversensitive response to chemicals/odours that occurs in MCS. It was amazing how this worked. I was doing this at a time when I was going through a few of the most stressful and scary years of my life over which I had no control. I did not do any meditation, relaxation or address any emotional issues, as I did not have the luxury of time for that, so I just learned how to recognize MCS patterns, interrupt them and go to a joyous memory for a moment and smile as broadly as possible!. The programmes train one how to do this. They also advise meditation and relaxation (which I'm sure would benefit me greatly!) but the essence of retraining is to break the pattern and generate a positive emotion.
Since it worked for me in spite of the fear and anxiety related to circumstances I could not change, I do not see why it could not work for someone on your medications. We are just retraining a faulty brain pattern( triggered by toxic overload in order to protect us, but going into over-kill!!!) which presents as MCS and all its wide ranging and horrible symptoms.
DNRS is used by people for anxiety and depression but maybe just start with the issue of MCS and keep things simple. When/if the time feels right for you to address other issues and consider reducing medication, then do take it very, very slowly over months or even longer with support from your doctor. A close friend came off benzodiazepines after many years by having a liquid prescription so that she could reduce the dose by very small amounts over many months.I think she would temporarily increase it a little if symptoms dictated. For some people I understand it may take even a year or two.
Try not to be scared that the programme will not work. Try not to care whether it will work or not. Just try it in as relaxed and curious a way as possible and see what happens. Take encouragement from every small improvement. Let the improvements come just as fast or slow as they want to. I felt I could get to grips with brain retraining once I took on this frame of mind.
Wishing you all the best if you decide to try brain retraining.