unable to update Apple Watch series 8 to WatchOS 26 after updating iPhone 16 to iOS26

I updated my iPhone 16 to iOS 26 on Monday. It took three hours in all, but I do love the updates to the interface. I have also updated my other Apple devices to OS 26, except my Apple Watch (which is an Apple Watch Series 8).

I tried to do the update from the Watch app on my iPhone, but it gives me this message (after opening the Watch app and navigating to "General", then "Software Update":

Update iPhone First

To update your Apple Watch, you first need to update your iPhone. You can update your iPhone software in Settings.

It gives me two buttons to choose from: "Open Settings" and "Cancel"

Tapping "Open Settings" takes me to the Software Update for my iPhone and it reports that I am on iOS 26.0 and that it is up to date

I also tried to do the update on my Apple Watch directly, but get this message:

"Unable to Check for Update"

An error occurred while checking for a software update

I get two buttons to choose from here: "Cancel" or "Try again"

I've done these OS updates previously and never had an issue. Anyone else encountering this, and if so, were you able to complete the WatchOS 26 update?

On a separate note, the iPhone Mirroring isn't working between my MacBook Air (on MacOS 26 Tahoe) and my iPhone 16 (on iOS 26). Not sure if that is related to all this or not.

Any comments or suggestions welcome!