A coastal drive in Sweden, two ferry rides, one from Sweden to Denmark and one from Denmark to Germany and the best of it all is driving in Denmark. The roads are not fancy but the country is beeee yutiFFul, in my opinion.
Then there is another way to do it, you can take a longer ferry to the northern part of Denmark and drive more in Denmark, that can be done with one ferry.
Then there is a third one where you take a night ferry from Göteborg to Kiel and then you are basically 60 km from Hamburg. And the night ferry is really fun, you have your own room, you have restaurants, bars, a casino, a small movie theatre, a library, slot machines for the losers and then two hours ahead of arriving to Kiel you get once fancy breakfast buffé.
I have tried all three routes and all have their times.