You have to eat for your training, even though the GLP1 will kill your appetite. If you are using the GPL1 to lose weight, then you are in a deficit. You should plan your deficit. Using a GLP1 for contest prep as a bodybuilder seems to be a great idea, but using a GLP1 in contest prep for a lifting meet does not.
The steeper the deficit, the lower the volume of training has to be. In a deep deep deficit, I only hit 2-3 weight training sessions a week and then I just walk. I cannot add any additional work or it messes up the entire process. You want to send the signal to your body to keep the muscle, training too much gives your body mixed signals. I especially avoid HIIT or interval type activities in the deep deficit.
Best practice seems to be this:
Plan out your protein requirements. You HAVE to hit these, even if you don't feel like it. For example, I need 250+ grams a day. I have to hit this, bare minimum to help maintain muscle mass in a deficit. I have to use protein shakes like Fairlife, protein powders, and beef jerky to hit this.
As far as training energy, try honey before training and during training. Why honey? It's easy to carry around a bottle and just suck some down. It also seems to hit fast.