How can I reset the passcode on my Apple Watch when I can’t get into the settings on my watch

Or you can also unpair and erase the watch using the Watch app on the paired iPhone.

https://support.apple.com/en-us/HT204568

1. Go to icloud.com and login
2. Open Find iPhone.
3. In the All Devices pulldown menu select your Watch.
4. In the resulting sheet that appears to the right choose erase Apple Watch. Select Next until the device is erased.
5. Then Remove the watch from your Apple ID.

This should reset the watch to the factory settings for your to setup as new and repair to your iPhone.

You can restore the watch from a previous backup if you have one.

M1 Mac mini, macOS 11.2.2; Watch, series 5 GPS/cellular, watchOS 7.3.1; iPad Pro 2nd Gen, iPadOS 14.4; iPad Air 2, iPadOS 14.4; iPhone 12 Pro, iOS 14.4; TV 4th Gen, tvOS 14.;  HomePods, audioOS 14.4 and Airport Express w/ Airplay 2