Most kids complaining (loudly) about being bored are from my experience those that are over-saturated with TV, phones, tablets etc. that are almost always around. Once you remove this (ie trip to remote nature/vacation), they can go slightly mental for a while.
It seems to me that the recipe for that ideal self-sufficient-loving-smart-social-over-achieving kids that all parents seem to want to have is sort of a pipe dream, and it always has been, just environment changed. We all want them, but few will end up being one and its often not that much a fault of a parent.
Plenty of love, plenty of time together, some time alone, some with others, well-managed discipline seems like a good start. I would add some traveling and exposure to foreign, exotic cultures. One can't avoid screen time these days, I mean if I want to show my kid to parents during Covid, it has to be via webcam. But passive aimless consumption isn't one for me, and for sure it won't be for my kids. I'll rather put them into rock climbing course.
What happened to topics about billionaires forbidding the access to phones & TV to their kids before age of 7?