I'm in a similar situation to you - BMI of 43, hypothyroid, on thyroxine 125mcg/d. Have lost about 2 stone over the last 2 years, with a lot of effort and doing exactly what I was told to do, trying to cut down my intake and doing a shedload of exercise - I tell thin people - mainly doctors who say I should do more exercise - that I do more exercise than them (true) and they think I'm making it up until I show them what it says on my Fitbit.
I asked to be put on Ozempic on the NHS so that I could lose weight and stop myself getting high blood pressure, diabetes, etc as they seem so fond of telling me I'll be getting those soon, but apparently I have to already have diabetes before they do that. I'm sure that at some point NICE guidelines will be changed, but all that moves very slowly and I just can't wait.
I'm self financing, have talked to a private doctor (eyewatering but I'm lucky in that I earn a reasonable salary so I'm convincing myself it's worth it) and started the 0.25mg dose about a month ago. I just started the 0.5mg dose this morning.
So far I haven't had too much in the way of side effects, and my appetite has definitely decreased - if I eat more than a certain amount, my body just says - no more - and I feel full and a little sick and stop. Which is great, as over Christmas I've had no fewer than 6 Christmas dinners with various people/groups and have not put on any weight, in fact may have lost a pound or two.
I'm hoping that the higher dose and going back to trying to lose weight will have some results, but for now it's unheard of for me not to put weight on over Christmas, as it's scuppered many diets, so I'm very happy with that!