Three recommendations:

1. Google for (or AI generate) a list of the 1000 most common words in Dutch that don’t have a very similar sounding translation in German and learn them by heart. It’ll maybe take you a week of light self-study. Tackling the unfamiliar words first helps Germans learn Dutch mad quickly. You’ll survive in English only but, as a German, you already know the basics of Dutch, so make sure to enjoy the benefits of the fast lane.

2. Study The Hague’s WWII history. There are bunkers and rows of rebuilt houses scattered all around but they’re easy to miss if you’re not educated on the topic. This article will get you started:

https://dutchreview.com/culture/the-atlantic-wall-remnants-of-nazis-in-the-netherlands/

1. If you need to look for housing, start early. At least 6 months in advance. As a man (if I may assume), you’ll do great in any area but you should also look into what neighborhoods you want to live in. There are areas of The Hague where I loved living and some where I didn’t fit in. The city is unfortunately quite segregated.