You can’t roll back updates. Should have read what was new with Watch OS 10. It’s been out for a while now so information is everywhere about the changes.

It just officially started rolling out in the US about a week now. It may take time for your device to be “next in line”

Yep, I learned that same thing the same way. Sucks

you are a few months too early. just stop and wait

you have 2 or more months for this. no one knows exactly, but it is always a pre-order credit for accessories and discount on watches/earbuds/tablets.