For our next kingdom, let’s look to the stars.
There are many fascinating kingdoms in the Mario world — Mushroom, Koopa, Cap— but the one with the happiest citizens has to be Princess Rosalina and her Kingdom of the Lumas. Now, all Mario series Kingdoms have their flaws. After all, the Kingdom of Lumas uses their food as their currency. Not a perfect model for an economy. However, unlike the Mushroom or Koopa or even Cloud Kingdoms in constant states of kidnapping or death-by-plumbers, this kingdom is relatively peaceful.
Up in the stars, Rosalina and her Luma subjects/adopted family live in a relative sea of tranquility. They travel around the stars, watch the amusing chaos below from their Comet Observatory, and (mostly) avoid all the Bowser shenanigans. Even when Bowser attacked during Super Mario Galaxy, the worst thing that happened to the Comet Observatory and the Lumas was a shutdown period and some mild hibernation while Mario and Luigi collected stars (assuming you collected all 120 stars and got the good ending). Definitely not the worst thing that’s ever happened when a Mario villain attacked.
It’s no modern civilization with TV and pizza, but as far as kingdoms go, The Kingdom of the Lumas is hardly the worst you can do for yourself. If you got isekai’d into a video game, Kingdom of the Lumas is a great way to avoid turmoil. Instead, you can just sit back, watch the stars, and nibble on some star bits.