I use the Nomad Rugged band on my Ultra watch and love it. It’s rubber so it can be washed and it’s easy to remove and put on. I mountain bike and run with mine and it holds up to it.

https://nomadgoods.com/products/rugged-strap-v2-ultra-orange-black-hardware?gad_source=1&gclid=CjwKCAiAx_GqBhBQEiwAlDNAZm1iaNb8iHKPXq0ieHHSZMDvWA24REHpsWhCr1KJmX_XZIKA4NIoJRoCrikQAvD_BwE

I mountain bike and I see a lot of them among mountain bikers.