I finally found out how to activate the overbridge driver in Sequoia. Apple moved the driver extension settings away from the Security and Privacy tab. Go to Settings -> General -> Login Objects & Extensions. There are now 2 things on this Screen: First the “Allow in the Background” section, someone else posted above, which should contain the “Elektron Music Machines MAV AB” object. This should be activated. Second, if you scroll down on this screen there should also be a section called “Extensions”, one entry should say “Driver Extensions” or something like this. Click the information (i) button, there you can activate the overbridge driver.