Lolland-Falster is an hidden gem. The most popular spot is Farø (Faroe) with its spectacular view of the Farø Bridge. The wind gets funneled and is almost a few knots more than the forecast. It is relatively close to Copenhagen (approximately 1 hour from Copenhagen), which is why many city-surfers takes the ride to avoid the much crowded spots in Copenhagen. On a good day you will have about 50 kites on the water. As the spot is located on an area connecting to island-like land areas, you have the option to go on either side of the road. Launch area is excellent.
You will also find smaller wave spots close by.
However... if you are willing to go another 45 minutes from Farø, you'll hit the isolated pancake-flat water spot, Albuen (Elbow), that works in all wind directions (West angled wind are preferred, east can become a bit gusty). On a good day you will find about 10 kiters on a 6000m2 large spot. That is 600m2 per person... on a good day (I have never seen more than 8). As it is rather far from civilisation (in danish standards) there are camping, caravan and cabin accommodation 500m from the spot. It doesn't get any better than this.