To get your cat interested in eating you can try adding:
- a pinch of parmesan cheese to the top of the canned food
- a tiny pinch of cat nip
- a dab of melted butter
- a bit of freeze dried chicken treats such as PureBites
Try slightly warming the food just enough to release the aroma - do not microwave, also make sure the dish & the food are not hot
Unusual for a cat to have low thyroid levels that is more commonly seen in dogs where cats are usual end up high. I'd have that re-tested in about 3 months.