Hi, I'm Bhavik. Welcome to JustAnswer. I'm reviewing your question now, and will reply back ASAP.
Please tell me name of those apps which you are not able to uninstall . So system application and programs can not be uninstalled as they are part of our windows 10 software package. If that application is user application then we can uninstall it.
Which sync setting you want to turn off ? Are you using any software to sync ?