Chess players fight for the center squares. Your center is sleep, food, and focus. Hold those and the edges follow.

Everything else runs on a small number of basics. Sleep, eating regularly and protected attention are not side issues to be handled once the important things are done, they are what the important things are made of. Lose them and every other effort gets harder for no visible reason.

Pick whichever of the three is currently weakest and give it a week of real attention. A consistent bedtime, meals that actually happen, one stretch of undistracted work. It is unglamorous, and it lifts everything sitting on top of it.