Hello, @jouzas! This website is one for those who develop applications for Apple products to ask questions and get help from fellow developers or Apple Engineers. It looks like you're trying to submit feedback, so highly recommend that you instead submit this through Apple's official iPhone Product Feedback page.

Thank you, @reed.1325 and @l00! I rebooted my device, and Device Hub is now working. I realized, by the way, that the simulators I created in Device Hub were being created in the Simulator app. Hopefully this gets fixed in the next beta