I've tried a few bread recipes but I am by no means an expert. However, this recipe is the best bread I've made to date. It uses 3 grains (or their flours if you prefer) and requires a strong blender (like a Vitamix) but no bread machine. I use it to make English muffins or a loaf of bread. The muffins are a little easier to make and the bread comes out in premade portions. It passes the sandwich test and it tastes great over several days (to my taste, store-bought gluten-free breads tend to lose their flavor on the second day) This recipe is pretty flexible in terms of varying ratios or types of grains.  https://www.instagram.com/p/DPDnyaJjpHh/

I don't have a bread machine but it sure looks like the bread I remember from BC. This is on my "to do" list.

I think seafood in general will be high in iodine.

This recipe was created by a scientist and posted years ago. I will admit I haven't made it, but it's also supposed to be quite good:  

That sounds like really encouraging progress, and it is great that you are narrowing things down so carefully. It can be surprising how something like added iodine in a milk alternative might make a difference for some people with dermatitis herpetiformis-type symptoms, so your note may definitely help someone else who is still dealing with that last bit of itching. It also sounds like you are finding a more comfortable routine with almond and soy milk, simple safe meals, and watching individual triggers like tuna without feeling completely restricted. This really is a learning curve, and keeping track of what improves or worsens symptoms is often the only way to spot patterns. I hope the dermatology appointment goes well...let us know.