Yeah, the instinctive response to this would be that he is trying to distract from the Epstein files fiasco, but that in no way means that this is a trivial thing and Trump does not really intend to annex Greenland.
He is dead serious about this.
He distracts not like a troll, throwing extreme things out there that he doesn't really mean. He distracts by throwing things out there that are all part of his agenda, and every time he throws something out there as "distraction", he actually advances his agenda one more step by desensitizing people ... until one day we wake up and realize that he meant all his ramblings after all. Just because what he claims that he wants to do makes no sense to us in any way doesn't mean he actually doesn't believe it.
He is, as the parlance goes, chaotic evil.