I used a cheap double ring spacer one for a while. It’s bloody awful. You can put some superglue drops to attach the spacers to the hub or frame, but they eventually fall off, generally into the overgrown black hole. I think it’s a waste for such a nice hub.
I now use the Wolftooth Boostinator. Is not that much expensive and does things the proper way. It replaces the stock left cup and puts a spacer on the disc. You need to dish your rim some mm to the left but even a wheel building dummy like me could do it, it’s just a matter of tightening the non driveside spokes a quarter turn per pass.
You also end up with a stronger wheels as the rim gets more centered between the hub flanges