After my post with a prototype of a clock, I got good advice on how to get the latest Plasmate, and then I found another clock with a transparent background. So, I got to work to make my prototype actually work.
In the process, I lost the original QML file, so I had to start from scratch (or from a copy + paste, you know).
Here’s what it looks like, installed on my desktop.
You can find the code here.