Glycogen stores only partially deplete overnight. Thinking that you burn any significant amount of fat or carbohydrates while exercising is to misunderstand how the body works and how much energy is expended during exercise.
Increasing one’s basal metabolic rate by gaining muscle or being in a caloric deficit is what will lead to weight loss. Body composition changes can be attained by modifying the ratio of macronutrients you eat and the type of exercise you do.
Intermittent fasting is kind of a fad and over rated from a health pov. It helps to the extent it keeps you in a caloric deficit, but you don’t need to fast to be in a caloric deficit.
Weight loss is simple but not always easy. Just look at Ozempic. What do you know? If you eat less, you lose weight.
The fitness/health space is full of noise, but once you tune out all the BS it’s quite simple and straight forward.