what is the best museum (s) in Copenhagen to learn about Danish history?
The National Museum of Denmark. It a comprehensive museum of Danish history. The Viking section on the second floor has stunning artifacts such as Viking helmets, the longest Viking ship in the world and finely-crafted gold and silver jewelry.
Perhaps the Danish War Musem would interest you: https://en.natmus.dk/museums-and-palaces/danish-war-museum/
The National Museum in Copenhagen is superb. We we allocated 3 hours and did not finish before the museum closed. Organized chronologically. No language issues.
wonderful advice thanks to all!