Trump only accepts realities that he has created himself; partnerships, agreements, etc. only apply if they conform to his ideas.
And Greenland is not what Trump has “set his mind to”. The interest had been there for a long time, only because of the conflict with China it has now come back into focus.
For the USA, Greenland would be a real trump card in the near future, and not just from a security perspective.
As the ice melts, new trade routes will open up for shipping in the next few decades. One of these will be the transpolar route that runs via Greenland. It would give China a direct and easily navigable route to Europe from the Pacific. Economically and militarily, this would be an option for the Mallaka road.
However, each Arctic region has a 290 mile zone off its coast. A US state in Greenland would block China’s access. Switching to the Northeast Passage would not be an alternative, as it will not be continuously navigable in the future. Melting ice leads to pack ice and this to drift ice, which poses a danger to shipping.
China’s ambitions in the Arctic would therefore be on hold.