Opting out of macOS Developer or Public beta simply takes you off of the beta seed channel.
The best time to jump out of the beta program is after updating to the Golden Master (GM) version of the beta.
It will automatically download the latest stable version of macOS, and as long as you have a Time Machine backup, you can restore your Mac to the way it was.
RELATED: How to Fully Restore macOS From a Time Machine Backup in Recovery Mode To opt-out of the macOS Developer or Public beta channel, open System Preferences on your Mac.
When the next stable version of macOS is released publicly to consumers, you’ll be able to install it from the System Update section in System Preferences.