Limiting Windows Defender isn't more secure
It's not a good idea to turn off cloud-based protection for Windows Defender, as that limits its effectiveness. By turning off the cloud-based function, it won't be able to check to see if there is a signature match that has not yet made it into the system's list. You'll be more vulnerable to newly deployed malware.
If you want to turn off the cloud based option, then you'd be better off going with a different antivirus vendor and removing Defender altogether.