If I go to the page opera.com/connect, I get this message instead of the QR code:
"Install Opera
In order to synchronize your devices you need to install the latest version of Opera for computers."
Needless to say, Opera is installed, updated, and it's the default browser.
I also tried to reinstall Opera but the page keeps asking to install it.
I'm on Windows 10 Pro 64bit Version 21H2 Windows Feature Experience Pack 120.2212.4180.0
Opera version: 92.0.4561.21