Pulling the trigger is a fine motor skill, hitting the magazine relase is a fine motor skill. To say that someone won’t be able to hit the slide release is a common misconception. Training, training.
My shooters are required to do two-hand reloads, two-hand malfunctions drills and also one-handed and on-hand (weak).
If they can hit the mag release to do a one-hand tactical reload, they can hit the slide release.
Of course it is wise to practice and know as many methods as possible. Hitting the slide release, using the rear sight on your belt or boot heel, etc.