Turning land from undesirable to desirable is only a matter of energy. Lower time preference. That's why we prefer homesteads.
Discussion
It's really hard to do without a ready water source.
More energy required. Diverting water is not a new invention. The aquaducts were a huge factor in Romes success.
Yes. That's not something one family can do while trying to survive.
Rome wasn't built in a day.
Sure, but that's beyond the scope and capabilities of even small communities. It's possible, but not likely without much backing from a wider community. (I'm not wanting to involve any gubment since I don't believe in that.)
Government is an emergent phenomenon. Like money. The goal is to localize it to the greatest extent possible.
Just look at the Great Man Made River of Libya to see what can be achieved.
Desalination is again just a matter of energy. I'm sure Bitcoin miners can directly help with that.