So was I :-)

If you're talking about a freestanding handstand, held for 15-20 seconds, then I would bet a beer that your confidence is misplaced. It's surprisingly hard, it requires a lot more strength than you'd think and the balance take a lot to learn.

You don't have to take it from me, you can take it from Jeff Bezos's friend's handstand coach: https://www.inc.com/tommy-mello/in-a-recent-shareholder-lett...

This is my guess.

If writing an article that says 0-30 then you have to assume worse that that - someone who has never run a mile.

Is there really anything fitness wise that a person who literally has never run a mile can do in 30 days?

You might as well criticize this by saying that an 80 yo couldn't do this in in 30 days.

depending on what you are doing now, you could also focus on continuous breathing so that you don’t hold your breath, which can be a normal reaction to doing something with power, but limits endurance

Mixing interval training and steady state cardio works wonders

I'm also uncertain how 50kg is the weight of a normal person. If I get below 75kg I'm around 5% body fat, and I'm barely above the US male average height. Getting to 50kg would mean losing a substantial amount of muscle mass, I literally have never had enough fat and so little muscle (even when I was obese) to be able to healthily cut down to that weight. And, again, I'm only about 1cm over the US average.

In this paragraph you seem to be interpreting "A normal person at 50kg" from the parent comment to mean "the average person, who weighs 50kg", when what they are saying is "a 50kg person who is neither too fit not too out of shape". A slim (but not extremely thin) 5'4" (1.62m) woman weighs around that much.

Please be careful.