My gal-dog loves 2-ball so much I have to make sure I don't over run her. My big-boy, even if I have what seem to be 2 identical balls, has a favored one. He will chase one with joy and barely go after the other. He prefers tug so I use a wobbly flyer by Westpaw. I can toss it and I can tug it. When it is time to end the game I take the toy and exchange it for a leaf...yes, a leaf. He loves chasing them since they fly slow and randomly. I have to be careful when they get too old and dry. They get too crumbly and I don't want him to breath them in or swallow the small bits.You're not alone, I play keep away. He adjusts his speed to fit the chasee. He runs faster for me than my husband. My dog wont play 2 ball or 2 frisbee. He stands, waits, then looks at me to tell me "You threw the wrong one'.
As far as being trained to "out", some people think "my dog knows the word" and others think, "I expect my dog to obey every time". I expect mine to obey every time BUT I also recognize that sometimes it is hard for them and I wait it out. It feels like forever but after watching myself on a video I can see that it is only a few breaths. Getting a quicker more consistent out is one of our goals for 2020.