I have been searching a few foreign sites for protectors, but the overall quality was film protectors (PET). I was looking to find glass or, at least, TPU.
I managed to find two options on Amazon that are somewhat decent:
This “custom fit” protector is close to something by Zagg (TPU), but will take about a month to arrive.
https://www.amazon.com/gp/product/B081L25H82/
This is a glass protector made for the Canon 6D and has prime shipping.
https://www.amazon.com/gp/product/B0757DSZYF/
Please note: An exact fit for the 6D is too large for the watch and many protectors are returned as too large for the 6D. I have tested multiple and this one fits almost exactly like those included with some watches. It was reported as too small for the 6D.
https://www.amazon.com/gp/customer-reviews/R2Q39HCGRYR596/
Hopefully this will save someone else the time or hassle) of finding one.
Thanks to mica for the idea to investigate Canon 6D protectors.