Had the same problem and solved as follow on MacBook Air M1
0) Unplug your screen/dock and shut down DisplayLink manager
1) Run the cleaner (choose everything and reboot)
https://support.displaylink.com/know...tool-for-macos
2) Download and install latest version of DisplayLink manager
3) Accept all notifications
4) Ensure that Display Manager is allowed under System Settings -> privacy and security -> screen recording
5) Ensure that allow new accessory to connect is set to always or ask for new accessories (System Settings -> Privacy & Security - > Scroll at bottom)
6) Plug your screen/dock and wait. If it does not work unplug and try another usb-c
It took me a couple of attempt, now it works