Read through this thread. Here's what I did to get mine working:
macOS Catalina 10.15.1
I had installed the latest version 5.2.1, but when I plugged in the dock, my MBP screen kept flickering on and off. did all the suggested steps including
https://support.displaylink.com/know...-functionality
so I uninstalled this version and installed 5.1.1 (older downloads section), still din't work. so then I disconnected the dell dock and connected it to a Dell Laptop and upgraded the firmware using the dell dock firmware utility updated to the latest it found (0017)
Still running 5.1.1 and now the two external monitors I have are working.