Unable to upgrade to WatchOS 9.2 (Apple Watch 4 Series with 16GB RAM)

Try these steps:

1.    Make sure that your Apple Watch is connecting properly to its charger. 

2.    Restart your Apple Watch.

3.    Restart your paired iPhone. (while the iPhone is restarting)

4.    Try again to update your Apple Watch.

If the update won't start:

1.    Open the Apple Watch app on your iPhone.

2.    Tap General > Software Update.

3.    Delete the update file.

4.    Try again to update your Apple Watch.

Learn what to do if you see 'Cannot Install Update' when updating Apple Watch 

or if your Apple Watch says you need more available storage to install a watchOS update."

Possibly if it is very full

 Unpair and erase your Apple Watch

On Youtube, https://www.youtube.com/watch?v=UXBcNcbTcqg&list=RDCMUCYFQ33UIPERYx8-ZHucZbDA&start_radio=1&rv=UXBcNcbTcqg&t=25

and then

Set up your Apple Watch without restoring the backup

Or in Youtube https://www.youtube.com/watch?v=7rb3vX86RUQ&list=RDCMUCYFQ33UIPERYx8-ZHucZbDA&index=3

then

Update your Apple Watch

If you've completed that troubleshooting and the issue is still not resolved, Contact Support.

Click here > Contact - Official Apple Support

or phone numbers 

Click here > Contact Apple for support and service - Apple Support