How can I uninstall watchOS beta I accidentally installed?

You have to send it into Apple to have it reset. Apple Store cannot perform the reset. It's in the developer release notes.

You ought to reach out to Apple Support directly. You should be able to reach them here  Click here > Contact - Official Apple Support  or phone numbers  Click here > Contact Apple for support and service - Apple Support

Or update the iphone to iOS17 beta the same way you got OS10 but we can't help or support you if you do.

Hello Laerus,

We're not allowed to discuss the beta software here.

I'd advise going to Apple Developer's forums and asking your question there.

Its ok, we can advise how to remove it but that's all.