I had a TSH and T4 test every year and they always told me it was normal. In that time I just got more and more tired and the goiters on my thyroid got bigger and more numerous. The tests are worthless in my opinion.
I finally started taking Iodine. Now I am at 50 MG a day but considering raising it. I studied Iodine and the thyroid in depth. It is basically impossible to take too much iodine. The body is designed to eliminate any excess almost immediately.
I would suggest you look at the food you eat. I don't know the details but some vegies actually irritate the thyroid. Cruciferous vegies for one.
Low salt and magnesium also greatly affects the thyroid.
You can't continue eating the same things and expect improvement. Nutrition is the key. People are stuck on this thing with Kale now. Kale has negative side effects.
It seems too simple so people don't look at their diet. But the simplest answer is usually the right answer.