Basically it sounds like you want to disable the lock/unlock button on your phone so that the only way to operate the lock would be to do it physically using the keypad. Is that right? If so the only way to do that would be using a custom device handler which removes those buttons, but you can’t get rid the lock/unlock functionality since that’s needed by ST to operate.
There are additional ways to build in security, like use autolock so that if it’s accidentally opened it’ll lock itself.
You can also use a notifications rule to notify you everytime the lock is unlocked (e.g. if you’re using the Lock Code User management app, you can set it to notify you on a manual/remote unlock/lock and also auto relock it if your hardware doesn’t support it) or you can setup a rule in CoRE/WebCoRE etc.