Hi @ARK35, sorry to hear about this.
Have you been able to test if the power key works better in safe mode? Safe mode is a troubleshooting mode where all apps downloaded from Play Store is temporarily deactivated. By doing this, you can see if this behaviour is caused by a downloaded app. For more information on safe mode and how to use it, click here.
If the behaviour persists in safe mode, I would suggest that you try to repair the software on the phone, as there is no setting for this. Keep in mind though that a software repair will erase all user data from the phone, so make sure to do a backup before the repair.
Try this and let me know how it goes!
