Hey there @willi80!
This may be a little late for you, but if the machine is managed by Curry's, the only way to remove management would be to contact them, as removing management from any ChromeOS device is next to impossible, and the method for removing it has the potential to destroy the device. Hopefully, they will remove the management and you'll be home free! For more information, you can check out [link|https://www.ifixit.com/News/43450/how-to-reset-a-managed-chromebook-and-avoid-enterprise-enrollment-you-cant|this article|new_window=true]. The focus is on Chromebooks, but the principles will be the same for any ChromeOS machine.
Hope this helps!