I didn't have to go far down the page before I read this:
"1.Iodination of tyrosines on thyroglobulin (also known as 'organification of iodide')."
So we might conclude that there's a snare in your organification pathway, and for that the Iodine Docs formulated ATP CoFactors. Each time-release tablet includes Vit B2 100 mg and Vit B3 500 mg.
The suggested daily dose of ATP CoFactors is 1-3 tablets per day, not all taken at the same time. Each tablet can be snapped in two, and I take one half four times a day. It feels better than taking just one whole tablet.
Will this lower your thyroglobulin? I have no idea. This just seems a reasonable place to start.
FURTHER NOTES --
I don't know what to advise since your country does not sell even Vitamins B2 and B3, let alone ATP CoFactors. If you can't buy them and can't import them, find foods that are generally high in Vitamin B. I'm dissatisfied with that answer, but there we are.