Hi,
I have nothing published about how it can be done.
It is somewhat complex.
You can download my watch face for free with a stopwatch built into the samsung store app.
Look for the watcg face in the samsung store with the following name:
Sport S-60M
Watch the video on YouTube of how it works.
https://www.youtube.com/watch?v=lRavVxyTRB0
(Sport S-60M) Watch face for Samsung Galaxy Watch, Watch Active, Watch Active 2, Gear S3 and Gear Sport
I don’t know if it’s what you’re looking for.
Greetings,
Sergio