How to enable device pairing in Google Messages?

On a ULEFONE NOTE15 running Android 12, fully up to date, and am trying to get the QR code reader to launch from Google Messages on the phone in order to pair with Google Messages on a desktop computer. I installed the Gamma Play QR code reader to scan the QR code for Google Messages and confirmed that, indeed, I am currently using Google Messages. However, there's no option within the setting for Google Messages as expected in order to pair the phone's Google Messages with the website for desktop access. Scanning the QR code from the website with Gamma Play simply launches a browser on the phone, saying to select device pairing from Google Messages. There's no such option available from the phone version of Google Messages for some reason. version messages.android_20250 708_01_RC00.phone.go.dynamic Shows in app info. How can I pair this phone with a desktop for SMS?