If you have Spanish nationality, can you settle in Germany and become a German citizen? Or you can work in Germany.

That will definitely work in Germany! Upstairs, it is definitely unnecessary to say if you want to work and stay!

Because citizens between the old EU member states can work in other EU countries. At least the Germans I know are in Spain, and applying for social security number can get a job in the company. It's simple.

Spaniards also go to work in northern Europe, but not many people go to work in other countries because the languages are not very similar and the foreign language level is very poor.

As for becoming a German citizen, taking German nationality is another matter, but it is totally unnecessary. You can legally enter and leave Germany, stay and work. Why do you need citizenship?