I can't find any evidence that GLP-1 are catabolic to muscle mass. There is no evidence I can find that GLP-1s do anything above what calorie restriction does.
There is a linear relationship between calorie restriction and fat loss down to under 10% body fat. There is so much wrong information on calorie restriction from studies done on people who were literally starving with already very low body fat %. Then apply that to people with 25% body fat is just wrong.
Westerners trying to lose weight don't have this problem. I think part of the obesity epidemic is this insane idea that calorie restriction is bad. Everyone kind of understands the thermodynamics of calories in / calories out. Everyone even kind of understands the benefits of fasting. At the same time though there is this nonsense that if you restrict calories too much you start burning all this muscle mass. It is patently absurd.
Add up the calories of what a 250lb bodybuilder is eating for contest prep to lose fat and you will see they are "starving" too.