I have a golf umbrella that serves me well on the course. I have looked into an adjustable clamp/holder that can attach to a folding chair. There are many types of clamps available as well as a complete chair, clamp, and umbrella package.
Here’s a combination suggestion
https://www.amazon.com/HOBVO-Umbrella-Adjustable-Universal-Umbrellas/dp/B0CG5G959T/?tag=fabo03-20
