Copenhagen in my opinion is worth at least two full days considering that you will be recovering from a transatlantic flight. My flights from the west coast are overnight flights and I don't get much if any sleep.
https://www.ricksteves.com/europe/denmark/copenhagen
No experience with Sweden,
Oslo is worth at least a full day and if you want to enjoy Oslo instead of running through it, two days would let you enjoy the Bygdøy museums and sites. Its easy to walk around the outdoor folk museum for a couple of hours and there's the Viking Ship, Fram and more museums on the Bygdøy peninsula. Take the harbor ferry to or from Bygdøy. Roam the Vigeland sculpture park. Ride the T-1 T-bane metro up to the Holmenkollen ski jump and museum and view the city from the ski jump tower. And there are art museums if that's your thing and the Resistance museum is a must not miss.
https://www.ricksteves.com/europe/norway/oslo
One night in Bergen could work if you depart Flam early and get to Bergen by noon or so, but planning for two nights (full day) in Bergen would be less frantic.
https://www.ricksteves.com/europe/norway/bergen
If you are time constrained, consider doing Sweden during another trip, or skip Copenhagen and just do Sweden and Southern Norway.