Could the problem with soy be one of under medication. If you are on good levels of medication, in theory you should be functioning at a more normal level for yourself. To take a thought from STTM, as many people are undiagnosed and or are under medicated there must still be people with a low thyroid diagnosis who still have too many symptoms.

I was told to avoid all goitrogens and soy is a goitrogen. To my knowledge goitrogens suppress thyroid activity. The exact opposite of what I'm trying to do. I'm not far enough along in my treatment to start experimenting with what foods to keep yet, I'm just on the elimination side of thngs.

Something you may want to research is raw soy vs cooked soy product. I have heard some say that cooked soy is ok to consume with thyroid medications but that raw isn't. I don't eat any soy just as a precaution, knowing that it can potentially interact with my medication and render if less effective.