If it says OPEN then it must be on the Watch somewhere.
Try "Hey Siri open Wallet"
If you still cannot find it, First force restart the Watch
i.e. press and hold both the side button and Digital Crown for at least 10 seconds, then release both buttons when you see the Apple logo.
Then, although it may seem irrelevant, while it is restarting Force Restart the paired iphone Force restart iPhone – Apple Support (UK)
You may also want to make sure the software on the watch and iphone are both up to date to the same level. Updates are in pairs.
Update your iPhone or iPad - Apple Support
Update your Apple Watch - Apple Support
Test it for a while. If it is still misbehaving... Unpair and set up again
Unpair and erase your Apple Watch – Apple Support (UK)
and then set up if necessary without restoring the backup - takes about 20 minutes
Set up your Apple Watch – Apple Support (UK)
Make sure you are not using VPN or security apps on the iPhone.
If you've completed that troubleshooting and the issue is still not resolved, Contact Support.
Click here > Contact - Official Apple Support
or phone numbers