To shoot a red dot in bullseye well, you have to choose: focus either on the target or on the dot. You can’t do both, or go back and forth between the two. Here are techniques from Brian Zins to properly aim a pistol red dot sight
The trigger is the only part of the gun that’s moving during the aiming process. If you are having trouble with precision pistol aiming, this video with Brian Zins about “aiming through trigger control” will help.