Exercise should be once a day or within three days, and you don't have to go to the gym to exercise. Didn't China Wushu masters and Muay Thai masters stop exercising when there was no gym?
Therefore, the key is to find a suitable exercise method. In fact, even if the high school homework is heavy, you can actually take some time out to exercise every day instead of half an hour.
I recommend you a book, Prisoner Fitness. You can become a master by using your own weight and simple equipment in your own room, and the exercise effect is better than that in the gym. Videos and PDF files can be found online. Exercise should never be exposed to the cold, but should be carried out step by step.