Perhaps look to catapult, consistent, accurate, simple.
A 'potato gun' would need a very precise volume of air compressed and delivered to the tube, otherwise very accurate and consistent. ( don't overdo this one, it can become a cannon.)
A sling shot much like a crossbow could work, repeatability for accuracy could be overcome, a spinoff of the catapult.
10 meters is no problem with a golf ball, the dimples will have little effect. You might start with the math, the weight of the projectile, the amount of force needed to follow a planned trajectory, then experiment to fine tune your launcher. Put the ball into a pea soup can repeatedly should be acceptable.