Spring break in Germany and...?

There is always good old Rothenburg o.d.T, They should like the Nightwatchman tour, Crime and Punishment Museum, walking the ramparts.

There's a lot to see/do in Munich and in other nice places that are close-ish. Please guide us a bit more... can you share the interests that you and your teens might have in common? Right now we only know that you doubt Salzburg will interest them.

Munich: with just 2 days I must recommend against a day trip to Neuschwanstein. The 25-minute tour is not worth the 5 hours getting there and back. I am hesitant to recommend Dachau, which isn't that far away, but... it doesn't sound like something most teens would be eager to see, and it really is not going to add anything to your understanding of what Germany is all about. You and your kids already know this part of German history, right? If you are like most Americans, then the Nazi-era, WW II and the Holocaust are the only things you remember about Germany from History class. So why not expose yourselves to some other period of German history? With Neuschwanstein off the table, you could head to Nymphenburg Palace - which is right in Munich, where Ludwig II, the Bavarian King who built Neuschwanstein, spent his childhood years and was coronated. There's a ton of stuff to see from that historical period. One family's experience:

https://www.theworldisabook.com/16991/munich-with-kids-nymphenburg-palace/

Since you want to visit Germany and not Bavaria only, how about Berlin which is 4 hours by train? Both cities belong to Germany but are very different culturally. Berlin is unique in its offering of world history and also of art and music.

With 7 days a split of 3 days Munich and 4 in Berlin makes sense to get a taste of both. Flying out from Berlin is then the best option.

Knowing gender, age and interests of teens would make recommendations easier.

Nürnberg and Bamberg are both not too far from Munich and are excellent visits.

But it depends on your interests; Nürnberg is full of history and Bamberg is full of beer.

If you want to visit the Alps Garmisch-Partenkirchen and Mittenwald are both easy train trips.

Bamberg is full of beer

I disagree on this misleading simplification for this beautiful town. Bamberg is known for its world cultural heritage. Smoked beer does not play a larger role than beer breweries in other cities. Info: German breweries produce 5,000 - 6,000 different beers.

As someone who believes that Brauerei Spezial in Bamberg makes the best beer on the planet, I will respectfully disagree about the importance of Rauchbier to Bamberg. ;)

I love Bamberg and it absolutely is worth a visit beyond beer. But would it be on most people's top 2 or 3 destinations in Germany for a first-time visit? If you are a beer aficionado then the answer might be yes, not only for the half-dozen breweries in town, but the many in the surrounding area.

If they are into cars, then Stuttgart for the Metcedes and Porsche museums

I lived in Augsburg (50 miles west of Munich) for four years and love that city. It is over 2000 years old and worth an day or at least half a day.

Nurenburg and Bamberg are great options.
Also, recommend Garmisch, Berchtesgaden (and nearby Salzburg, Austria).

The Romantic Road goes through Rothenburg ob der Tauber, Augsburg and some other walled medieval towns.
https://www.romanticroadgermany.com