YES!
I live in Hamburg, but right on the line to Schleswig-Holstein (literally--our dog walk route includes both states and our grocery store is in S-H). The clubs I am in are all in S-H, and our search and rescue team's training schedule means we get around a fair bit! Also, I am currently on a little getaway vacation at Timmendorfer Strand / Scharbeutz, a pair of Baltic beach towns near Lübeck.
The picture they included of my beloved Glückstadt doesn't begin to do it justice, and it is my absolute favourite place in S-H.
We love taking our horses to St. Peter-Ording for a beach gallop. If you know how to ride there are stables with beach rides for visitors.
Ratzeburg should have been included in this series--absolutely love it there. So should Wedel, which is the first suburb to Hamburg's west (and still on the S-Bahn line), which is absolutely adorable. It has a fantastic Roland statue. Just beyond Wedel are the sand dunes of Holm, a great place for geology and a picnic--a stunning and fascinating forest and sand dunes landscape.
There is a little "village" (generous term) called Neufeld that is absolutely stunning, and the seal station at Friedrichskoog is worth a visit. Sea breezes, dike walks, wind-in-the reeds feel with birds--so many birds. Stop in Wilster on the way back to civilisation for another cute town.
The caves (including a bat tour) in Bad Segeberg are well worth the visit. And as the recommendation said, Schleswig and nearby Haithabu are top places to go if you like history. And naturally the islands are must-sees. That means Sylt or a ferry to Föhr or Amrum, the Halligen, and of course Helgoland (and yes, spring for a few days there if you can rather than just the day trip). The Halligen in particular are unique, and the red cliffs of Helgoland are great for bird watchers. The history tour there is also great!
Visitors should know that up here, our population is thin and our verbosity equally so. We are all about sheep grazing on dikes, breeding world class horses, listening to the gulls, and having our curls straightened by the wind (what most people would call windy we consider a nice breeze). We eat Matjes and Krabben, speak Platt, and make everything out of brick. We have major waterways and small lakes, marshes and reed roofs and bikes and lighthouses and beaches.
It's absolutely stunning and definitely overlooked. But if you want to imagine what life in Europe has been like for centuries, look no further.