You can drop out of the beta and you should get an OTA to take you back. However last I heard from others they are still waiting on their OTA. So that might require waiting a bit.
Anything else will wipe the phone. Unlocking it will trigger a wipe. If you are already unlocked you could do it....But you are not.
Everything you mentioned will wipe the device. The is no way to go back manually. The only way not to force wipe the phone is to wait for the release version of. 2 in a few months.