Not everyone does well with rotary cutting, I know. But it is a skill, and one that you can improve at, unless you have physical issues that get in the way of making good cuts.
Consider finding a quilting buddy who is good at (and enjoys) making accurate cuts. If you can reciprocate with a skill (or your time or space or even pay), it could solve your problem.
Of you can buy the precuts that are out on the market now. Many quilts don't require much additional cutting from the 5 inch squares and the 2/5 inch strips.
RST