Suggestions for standing pole for sun shade
A 4x4 would work, and it mounting there is probably ok assuming the concrete is thick enough at the bottom which is below the bottom of the slab. Which it probably is, I would expect 6-8 inches +. I would use Simpson SDS concrete screws, 1/2" diameter and embed 4" into the concrete. Two of them. You'll need a rotary hammer drill to predrill the holes.

I suggest using pressure treated wood or cedar for resistance to rot since this is considered a wet condition.

Note that the higher want to mount it the more force on the post. More force in wind storm. More force to be more taught, keeping it very taught requires quite a bit of force