It's not the TSH that's concerning, it's the Free T4 that's above the reference range, that's bothersome... TSH is only a messenger hormone and when we're on replacement hormones, it's basically useless.
With congestive heart failure, I'm sure your thyroid hormone dosage will be lowered, even though your Free T3 is only at 52% of the range, since they won't want to risk any further damage to your heart.
It sort of becomes a "catch 22" sometimes... we have to lose weight, but we need thyroid levels high enough to allow us to do so and often our doctors won't prescribe a high enough dose of medication. My guess is that your thyroid levels haven't been optimal for the 20 yrs you've been on thyroid medication or you probably wouldn't have doubled your weight, which is very unfortunate...
I'd have to wonder, at this point, if you're diabetic or bordering on it (pre-diabetic or insulin resistant)... that can have a lot to do with whether or not we're able to lose weight or if we keep on gaining, as well. Insulin is, often, called the "fat storage" hormone.
It's important to note that vitamin D deficiency can cause a lot of symptoms similar to hypothyroidism, but it cause hypothyroidism or make hypothyroid symptoms worse...
Of course you need to lower the levothyroxine dose with the prescription of your consulting doctor. Also apart from that please check your Vitamin D3 level. If you have low or not optimal Vitamin D your hypothyroid symptoms may get worse especially when increase levothyroxine dose. If doctor is not willing to check do it in a private lab. The test name is
25-hydroxy-vitamin D3