Hello, Mh)
Welcome to the Microsoft Community.
Sorry to hear about your situation, it seems that you are experiencing the presence of the original Dutch language even after switching the system language to English.
This can happen, sometimes the system language synchronization is similar to a data synchronization, it takes some time to change all the languages in your system, so you can wait a little bit.
In the meantime, if you don't have the English language pack installed, you can download the local experience pack from the Microsoft Store and download the language you need.
Local Experience Packs - Microsoft Support
Best regards
Bobhe | Microsoft Community Support Specialist