Not doing anything is why you have no energy. The less you do, the more your energy levels drop, cos you're not doing anything. You have to actively use it, to keep it up. It's a negative feedback loop that people often fall into. "I'm tired, so ill rest", and then they keep resting too long, and lose energy as a result, so when they do try to be active, and feel more tired than previously, they rest even more, and reduce their energy level even further, until they're mostly resting, and still wondering why they have no energy.
The solution isn't to keep trying to "manage" what energy you do have, but rather, to lean into the difficulty when you can, and increase your energy levels by trying to be active, to then have enough energy that you don't feel a need to parcel it out so much. Gotta work your way back up to it. You can't "rest" or "recharge" your way out of lethargy. The solution is to try to work through it, not avoid it.
It gets harder before it gets easier, but if you stick with it, it does get better. You will feel more tired at first, because you're working yourself. That work is what will train your body to be more active, to meet the demand. Whereas continuing to do less will just keep training your body into doing less, and you'll always be more tired, no matter how much you rest.
I know there are other members on here who have also expressed the concern that they're always tired even though they don't do anything - this is why - you're tired BECUASE you never do anything. You never work past the tired to try to strengthen your stamina. One does not build strength by doing less. Like Neo when he first leaves the matrix or w/e - he's weak cos he's never used his muscles. It takes a positive amount of effort to overcome entropy, simply to stay in a neutral state. If you stop working past that point, you're already starting to lose ground.