I have the same issue with my young horse not respecting my leg. My instructor advised that I try squeezing first, then progress to a sharp kick and finally a flick of a schooling whip just under my heel if he doesn’t move off my leg straight away. It’s taking time but he’s starting to pick it up!
Dressage whip and groundwork. Sounds like he doesn't understand what you are asking, spurs will only make him more tense
Spurs helped me get the extra, out of my horse
Spurs would definitely work as an extension of your leg. You could also try riding with a dressage whip.