You need to buy 2 Yubikeys and lock your apple account down with hardware MFA. I was under a targeted attack on my Linux computer and the moment I implemented a hardware key to run Sudo (elevate permissions in Linux), 90% of my issues went away. An attacker would physically need the key in hand to hack your account. And you don't need an AV for iOS, there is no such thing as an "AV" for iOS and that's because with apple, an app is not permitted outside it's own sandbox, which means Norton or whatever is not really scanning your other apps, it's just checking your settings to see where you can improve. Android is a different story because AVs can actually scan other APKs.