None of that is correct. VO2max can be trained. You might not have the genetics to be able to reach 80 ml/kg/min like an elite professional endurance athlete but you can improve significantly from where you are now, if you're willing to put in the work. But just doing a bunch of running and hiking won't get you there. You'll have to follow a focused, goal oriented training plan. And it's going to hurt. This will also tend to boost natural testosterone production slightly, so there's a bit of a positive feedback loop.

If you have a legitimate medical condition then you can apply for a Therapeutic Use Exemption (TUE) to take banned supplements while still being allowed to compete.

https://www.wada-ama.org/en/resources/therapeutic-use-exempt...