Rugby or American Football, which requires more strategy, athletic ability, and which is harder to play?

Now, I’ve dabbled in American Football, and am currently a rugby player. I have gotten into this debate many, many times, but which sport requires more strategy? Of course, I have my own opinion of the question, but I would love to see other people’s perspective. Along with which is more strategical, which sport is harder to play, and which requires more athletic ability?