It gets burnt off as normal? Ozempic and co make the users feel less hungry so they eat less. A kilo of fat is about 7000 kcal, humans at rest use about 2000-2500 kcal a day, if there is a deficit of 500 kcal a day they lose two kilos of fat a month (on paper); total weight loss may be higher due to reduced fluid contents.

(disclaimer: armchair logic)

The average Western man burns less than 2000 kcal/day, I would say optimistically 1500 kcal/day for the people around me, most of them don't exercise much.

The problem with your computation is that the body is not stupid, when you stop eating, it stops burning. I don't know the exact numbers, but it is absolutely not linear like that.

So do you start sweating because of excess heat? Do you suddenly feel more energetic?

GLP-1 agonists seem to slightly increase resting heart rate, which might indicate a similar increase in basal metabolic rate.