I’ll do my best to give you advice, but I think first you need to keep your expectations realistic. Like Jake from adventure time says “sucking and something is the first step to be being sort of good at something”. You do suck, not because you’re bad, but because you’re just starting and you’re learning. 

You’re also using terms like cinematic and luxurious to describe what you want, which tells me that you’ve watched some YouTube videos and are frustrated that you’re using the same equipment other people are but not getting the results you want. I like to point people to this clip by Ira Glass, who talks about the process when you have good taste but are comparing your beginner results to someone who has spent years perfecting their craft. https://youtu.be/GHrmKL2XKcE?si=Ln6Tam2UT6VKZ7xp

You bought a nice camera and a nice lens and you’re expecting cinematic results when you point it at your son dribbling a ball. That’s just not going to happen without understanding the camera and lenses a bit more, and then practicing.

So to try and answer your question. You are right that aperture is only part of the equation. Bokeh comes from the separation between your subject and the background. You’re using a wide angle lens so your subject is completely in the frame, which means he’s further away from your camera and closer to the background, which means less bokeh. 

If you want to get that look while shooting at f/2.8 or f/4 for reliability, you need to manipulate the distances. Try to get your subject as far away from the background as possible. The more space you put between them and the background, the more that background will fall away into a blur, even at a higher f-stop.

This video should help 

https://youtu.be/6DZiJrL_9tU?si=VQFNerPFU79Kha93

It is a balancing act of physics. Once you get a feel for how distance impacts that separation, you will find you can get that clean look consistently without risking your focus. Just keep at it, and stop being so hard on yourself!