Hypothyroidism questions

51F, overweight, hypothyroidism, taking Unithroid 112mcg My THYROGLOBULIN is 2.9 ng/mL which my doctor said means it’s nearly dead. She said if it hits 2.8 or lower, she would recommend removing my thyroid. I was a bit taken aback by this. Does a non-functioning thyroid really need to be removed? Ultrasounds have always come back ok (no nodules), but last one indicated that gland was enlarged. I was looking back at my labs over the past 10 years, and when I was first diagnosed, my THYROGLOBULIN was 9.1. I’m curious: what causes THYROGLOBULIN to decrease? Original labs at diagnosis: TSH: 1.97 mIU/L (0.4-4.5) FT4: 0.9 ng/dL (0.8-1.8) FT3: 3.1 pg/mL (2.3-4.2) Antibodies <1 Thyroglobulin: 9.1 ng/mL (2.8-40.9) Recent labs (after years of taking Unithroid): TSH: 0.87 mIU/L (0.4-4.5) FT4: 1.4 ng/dL (0.8-1.8) FT3: 3.5 pg/mL (2.3-4.2) Antibodies <1 Thyroglobulin: 2.9 ng/mL (2.8-40.9) Also, based on original labs, is it possible I had (have) central (pituitary) hypothyroidism? Would treatment be different? Is it possible to have Hashimoto’s despite antibodies <1? Thank you for your time and expert opinion.