What I have read (sorry can't think of where) is that the idea is that you are supposed to only be on one of these Ozempic-style drugs for a short period, to get weight loss started: at the same time you are supposed to start a diet and exercise programme. The issue is, as the poster above says, is that over time fat and muscle will vanish, and muscle is so much harder to rebuild. If nothing else changes, as soon as the drug is stopped, the fat (but not the lost muscle) will be regained.
Edited - as I recall the ozempic treatment info is from Dr Michael Eades' "The Arrow" blog.