There is a huge natural variance between individuals that goes far beyond testosterone and includes height, bone density, vision, other hormones, etc. No one realistically expects a level playing field. But everyone has to play by the same arbitrary rules. In practice those differences only matter at elite levels; at casual amateur levels you can overcome natural disadvantages by training harder and playing smarter. The best player on your company softball team probably doesn't have a super high testosterone level.

Testosterone supplementation can induce erythrocytosis, but you can accomplish that more directly with EPO. (I don't recommend doing that.)

>at casual amateur levels you can overcome natural disadvantages by training harder and playing smarter.

no, it is just a feel good fairy tale. You're missing the point - amount of oxygen defines your speed/endurance/etc that you can reach. It is basic law of physics. Put a gas mask on and narrow the pipe half or even just a quarter - no amount of training will help you overcome that. I was an amateur boxer - 4th at University 30 years ago - so i'm not just armchair talking.

For the last decade i've been running and hiking regularly and there recently was a deep in my performance - pushing harder didn't work, it was just like hitting glass ceiling - which got corrected once i saw the anemia and corrected it with supplements. Did i instead have to accept the low level of performance, accompanied by easily setting fatigue, etc. just for sake of "naturalcy"? And if I to run some competition should I stop the supplements and try to run with anemia?

>No one realistically expects a level playing field.

exactly. So why wouldn't we try to to level it as much as possible. Wouldn't it make the competition more honest as it would allow to win the ones who train harder and play smarter than the ones who just accidentally got better DNA?

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...