The methods in use by Pegasus make it impossible to avoid. "Zero Click" malware allows them to take over a device without any interaction needed by the user so

The methods in use by Pegasus make it impossible to avoid. "Zero Click" malware allows them to take over a device without any interaction needed by the user so even if you factory reset the device, heck, even if you reinstall the OS entirely, Pegasus malware can get back into the device. Until the method they are using to break into devices is found and patched there will be no stopping it except for disconnecting the device from all networks or keeping it powered off. Edit: They are using 0-Day exploits against mobile clients that take advantage of flaws in default applications like iMessage. Pegasus intrusions have been detected on devices as new as the iPhone 12 running iOS 14.6. This would be a severity rating 10/10 for a CVE, to put it into perspective.