Are you sure that you’re not trying to cram too much into that space? It might feel very cluttered with all that in there. If you want a border, for privacy, it should be at least 1.2m wide.
Digging out a hot tub is a very, very tough job. Don’t forget that you are going to have to get power to it, and you’ll want to think about how to drain it (which needs to be done a couple of times a year). It might be better to locate it closer to the house on a concrete platform (this also makes it less of a dash in the cold in your bathers when you head out).