I agree with you, and your 2nd point about the b2b areas being important.

However I think the general math you do needs a bit more nuance. You'd want to exclude all people living in cities so you'd need to exclude the land mass taken up by cities to get a more accurate estimate.

Also I'm not sure where you get the 10% number from for people inhabiting the world. From this report they talk about humans impacting 15% of the landmass https://www.visualcapitalist.com/mapped-human-impact-on-the-...

Again, I agree with your point but I'm skeptical about your back of the napkin math.