Help my very big sad yard!

Sounds as though your yard would benefit from large trees, to which you could hand a swing, a hammock, or place lawn chairs /Adirondack chairs in vivid colors beneath. How about in ground posts, to which you could attach shade sails, or folding fabric, attached to cables, permitting retraction?

A pergola would help you stay out of the sun, and you could hang baskets of vining flowers from it, place a table and chairs beneath, with game boards for childrens' use. A storage bench could contain childrens' items, pillows, etc. A beverage cart near the house would be handy for iced drinks and so on.

You might consider planting a childrens' garden with a small sliding board, checkerboard built into a table, childrens' gardening tools.

A Maze of hedging would provide privacy, shade, and interest.

Colorful plants such as zinnias, cosmos, in planters will give you color until you plant an area in your yard for flowers.

Given your location, you'll need shrubs, trees and flowers that can withstand your heat and humidity.

Your artistry skills can provide many ideas such as oversized wooden or metal sculptures/ flowers/animals/insects for the yard.

Your dream garden sounds lovely Alisa and it would be amazing if you use your artistic talents to add some whimsy. We made some wood nymphs for our garden that you might enjoy doing. It's quick and easy. https://acraftymix.com/blog/2018/06/04/wood-nymph-garden-ornament/ I would also suggest planting lots of trees for shade and creating little secret gardens that people need to stumble into and be surprised by what's there/ Perhaps it could be a mall water feature or a fairy garden