A powerful study with 48440 (that's a lot) adult participants recently published by the British Journal of Sports Medicine demonstrates the importance of exercise and COVID-19 outcomes.
Consistently meeting physical activity guidelines was strongly associated with a reduced risk for severe COVID-19 outcomes among infected adults. Researchers recommended efforts to promote physical activity be prioritized by public health agencies.
This just outlines how important being active can help with dozens of health conditions.
Mainstream medicine does not provide funding for exercise based interventions and often supports treatments with dubious outcomes. See knee treatment culture war.
Know this, EXERCISE WORKS! If you appropriately stress your heart and muscular-skeletal system, it responds to that stress, adapts and builds all the machinery that is required to perform more stressful demands (lift heavier, faster, perform for longer).