How do I create a nice sitting area in my huge backyard?

You need a nice focal point like a fire pit or pond. Then put a garden around that area.

Millions. Google is your best friend. Here are some sites for ideas as well as how to landscape. I am sure you can find something to transform your dull and boring space. You are very lucky to have such a space, make the most of it! 🌞

https://www.countryliving.com/gardening/garden-ideas/g2314/backyard-ideas/

https://www.buzzfeed.com/peggy/51-budget-backyard-diys-that-are-borderline-genius

https://www.installitdirect.com/learn/low-maintenance-landscaping-for-large-yards/

https://zacsgarden.com/how-to-start-a-garden/practical-landscaping-ideas/large-backyard/

https://m.wikihow.com/Landscape-a-Large-Yard

Look at some gardening books and websites for ideas. Perhaps you can create a focal point with some flowering trees and shrubs, or a tree like a Japanese maple, with beautiful foliage? Maybe a pretty birdbath, surrounded by a nice garden?

Pinterest has a ton of ideas too. Without seeing what your space looks like it’s hard to say what would look good in your yard plus budget is crucial as that effects what you can do as well.