You can find a skill called "China Health and Longevity", which is also called "rejuvenation skill". It is the secret skill of Huashan Sect of Taoism, and the successor is Mr. Bian Zhizhong. I have tested this skill, and it is really good. It should be very suitable for your current physical condition.

Your current physical condition must be practiced quickly. There is no other way but to practice martial arts by yourself.

Besides, it's not called practicing qigong. This is a method of practice. Through practice, one can change one's physical condition and mental state. The ancients said: cultivate one's morality, keep one's family in order, govern the country and level the world. This is a way to cultivate one's morality.