Listen to the Rain

Your thoughts on "fun boredom" reminds me a little of this article, where the author goes out into a forest, makes a circle ten meters in diameter, and stays in it for 24 hours without anything whatsoever to do: https://www.theguardian.com/news/2020/jan/24/wilderness-solo-splendid-isolation-stopped-time-sitting-in-a-forest-24-hours . He is, of course, tremendously bored, and that was sort of the point of the exercise. He writes "boredom is the raw and unmediated experience of time" and eventually achieves a sort of meditative state.

For me, that article was the first time I'd considered boredom in a positive light. "Fun boredom" in video games seems like it might be similar.