The point of Mounjaro is to make you eat less, it does not in any way medically melt fat off you, as you seem to expect.
And yes, if you eat in a calorie deficit you should lose weight with or without it. But 'without' is easier said that done for most people.
The point of it is to supress your appetite so that you can re-train yourself into better habits than what presumably got you to a position of needing MJ in the first place. I'd be very surprised if you said this was your first attempt at weight loss , so why didn't those other attempts work?
Remember you have been on a non-thereutic dose to get your body used to the drug , it's not necessarily meant to work that well at this dose, although it does for many, including me.
Try the next dose up before you give up. While MJ is miraculous for some (including me, it's killed my temptations stone dead, I had a serious wine habit which just instantly went) it can cause others hideous side effects even at the lowest dose and then for up to one in four people it doesn't work at all.
Try the 5mg before you give up, but if you can stick to calorie deficit without it without falling off the wagon just do that . If I could do what MJ is helping me to do without injecting myself with an expensive drug, I certainly would.