Hi James,
Have you tried tzclock ? (it does transparency)
It is mentioned here: Best Free Clocks for Linux
and this is the homepage: The Knight
Download the debian version of both library and app ( because the ubuntu version is incomplete)
- https://theknight.co.uk/releases/Debian_11/amd64/libdial_2.2-1_amd64.deb
- https://theknight.co.uk/releases/Debian_11/amd64/tzclock_4.3-1_amd64.deb
Install libdial_2.2-1_amd64.deb first
then install tzclock_4.3-1_amd64.deb