Probably just need to be more deliberate with tricks and binds. Try dismounting from trapezes instead of dropping them (unless you mean dropping accidentally). Keep string somewhat taut in general for non-slack tricks. Bind more precisely with less string.
Also, I would recommend picking out the knots instead of unscrewing. Unscrewing runs the risk of wearing out threads, cross-threading, losing parts, getting the bearing dirty from dirt and string fibers, etc. I keep a toothpick in my wallet which won’t scratch the response area. I never unscrew my yo-yos except for bearing cleaning and response replacement.