The burnout that you’re pointing out is a sign that it is work. People who play video games competitively often go through burnout:

https://www.cbsnews.com/news/esports-burnout-in-video-gaming...

So I think about it as this: if I regularly feel pressure to complete tasks that I don’t want to, then it is work. This covers activities that one is not paid to do and that others may call hobbies. For example, training for a marathon as an amateur.