Since you’ve already got one tree, sink a 4x4 post in concrete (or just bury it if you want less permanence and like to live dangerously) to use for securing the other end of a hammock (with one end wrapped around the tree).

The post can serve double duty too - you could use it as a tetherball post (better to use a metal fence post in that case though? Or do they make dedicated tetherball posts), for either you or dogs.

So she got BS from BS

To be fair, my guess about the source of those claims is also totally unsubstantiated and quite possibly bullshit 😉

Does she hold any investment in BlueSky?

Imo, it’s way more likely she got her information about BS from the website/a press release/a contact at BS and like you said, didn’t bother to get a contrasting opinion from anyone associated with Mastodon (probably because it’s a lot harder to get ahold of someone from a distributed project like Mastodon).