Have you had the saddle checked? If it pinches the horse will be reluctant to go.
I wouldn't recommend spurs, I'd recommend a dressage whip. If he doesn't reply to your leg just press the whip near your leg, not hard, as if it was your leg, it's just an extra aid. It can also help you move their shoulders over or hind, and if they won't go forward just a very small tap on the bum and for most horse just the "threat" of being tapped with the whip will make them go forward without you actually having to even touch them.
Start with leg then if he doesn’t respond , tap behind your leg with the whip do this a couple of times while warming up for a couple of rides and soon you won’t need to do it anymore
Either use a whip or you can use spurs
Maybe she’s a bit stiff. Do carrot stretches on each side before and after the ride to loosen up jet muscles. It works!
Use a whip!! If he knows how to bend, make him do it. It’s easy to get frustrated but don’t give up. Just keep your horse in a circle and refuse to do anything else until he gets it.
Try carrying a whip when you ride
he never used to be like this, idk if it could be because he’s out of shape but he keeps refusing to bend and he runs me into corners and the fence. Any tips of advice?? I will not use spurs since he’s pretty quick on his own