Firstly, they explicitly state how to opt out of the beta during sign-up. You can completely leave the beta program or just use smart switch to switch back to the stable version but it requires a full reset of your device. Please read everything before you opt in to optional software
What's wrong with your NFC and Messages? For NFC are you referring to Google Pay? If so, it is normal that pay services are suspended during a beta test. They will resume when the official Android 13 is released. Figure 3 months from now, give or take...
If you just want out and aren't interested in troubleshooting or living without Google pay contactless for a few months, then read #11 in the FAQ in the beta notices that are part of this app.
If you need to withdraw from the beta, from Samsung Members -> Settings -> One UI Beta Program Status -> Withdraw. Then plug the phone into your PC, open up the PC version of smart Switch. Be sure to back up your phone since downgrading requires a factory reset. We recommend you try backing up your device and performing a master before moving back to Android 12.
