From what I understand from this video, they are using the DisplayLink technology via an app from the Google Store.
I doubt there is something cooked in Ubuntu Touch to take advantage of DisplayLink.

But when it comes to possibilities, this give me hope that with enough work it can be achieved: https://en.wikipedia.org/wiki/DisplayLink#Linux

As for the waydroid part of your question, I also doubt the necessary connection are available for the DisplayLink app to work as intended.
Best try it out to be sure :man_shrugging:

My best