I have met so many Dutch people who were excellent in German. I think once you speak Dutch and English people manage to learn German fairly well (many have said that they watch German TV and pick it up there). I have to admit that I have never tried to learn Dutch because people in the Netherlands spoke perfect English or German or both.
German is one of the foreign languages in which lessons can be taken at Dutch secondary schools. In my experience, many students had German lessons for at least 1 year. In addition, many older Dutch people are used to watching German television and so on, picking up the language.
However, in recent years there have been fewer and fewer students who choose German at school. Some have the feeling not for it and/or prefer English. I see something similar happening in French lessons. In other words, the knowledge and all of German decreases.
Although some are still building a foundation in practice. For example, one of my nephews has built up a basic level of German through his side job/weekend job at the market. Since he often works not far from the Dutch-German border, he gets a large share of German customers (who can understand Dutch often, but are not able to speak it).
I myself had 6 to 7 years of German lessons at school. But since my further education was mainly in Dutch and English, my knowledge of it dropped. When I went to work, German came up again (given suppliers/customers/other contacts). In addition, I noticed its benefits. At the moment I can speak, understand and read German reasonably well. Ok, mainly job related, but still

However, the writing is lagging behind, afraid of too many mistakes.
At one of the secondary schools I attended, there was an exchange with a German school (in North Rhine-Westphalia, near the border). Through that road we heard that on the German side, in the border area, students had the opportunity to take Dutch lessons. Unfortunately, that option was only available for higher grades than the ones we had exchanges with. But hey, in several cases it was even possible to communicate in the native Low Saxon variants.
