You should most certainly jump. If your shot is coming up short, that's a clear indicator you're missing power. That power comes from the legs. I highly recommend spotting up with your knees bent. Put yourself low to the ground before you catch the ball. If you already have the ball, keep your dribble low and again, have some bend in your knees. Then, when shooting, be sure to use that bottled up leg strength to elevate into your shot. This will provide the power needed to extend your range.
Do not worry about jumping messing up your shot. Right now, not
jumping is messing up your shot. Also, it should be worth noting that by "jumping" I do not mean jumping as high as humanly possible on every one of your attempts. Instead, I'd recommend just getting the leg bend going to begin with. Spring into the air and use the momentum of your low stance and movement upward to contribute to your shot power. Shooting is supposed to be one continuous motion. We start compact (knees bent, ball in shooting pocket) and it all begins to extend at once.
I know this is likely a pump fake, but this is still a idea of what one's legs should look like prior to beginning a shot (and the feet should be square to the basket).