Earlier quoted context omitted.
This kind of stuff masked you feel good to say but the UK isn’t going to stop the US if it (somewhat foolishly in my opinion) decided that it was going to take Greenland. Neither is the EU.
You are mistaking the battle for the war: Denmark / EU would no doubt lose the BATTLE for Greenland. Within hours. But the sun would rise the next day and the USA won't like the 'non-kinetic' consequences. Too many to enumerate. Eventually the adults in USA would just return it.
It's not an exercise we should entertain, though the EU needs to step up in a very serious way and spend billions of Euros adding new equipment to Greenland to beef up detection and defense.