What you said is true, usually a reliable antivirus scans for suspicious things or activities, so that it automatically takes preventive measures against it, and maybe what you mean is one of the antivirus applications that has a robot logo, right? Because I have used it, and it is really very reliable in doing prevention and security.
Other than that, I think it should be for anyone to install a reliable antivirus, so that they can avoid losses caused by attacks, and don't forget to always update when it is available, this must also be considered especially for a beginner, because I often find people who don't really care about antivirus.
I've been using iOS for years (and recently I've also switched back to Android). I've never installed any antivirus and never had my funds stolen from hot wallets installed on my phone. This means that if you maintain good security practices, such as only installing apps that need it, not installing suspicious apps and checking the permissions granted, the chances of you getting malware are drastically reduced.
But even so, we can't be careless with thieves.
Nowadays, it's very easy to use hardware wallets that connect to the mobile device, such as the Trezor via USB or air-gapped hardware wallets where we can sign transactions by scanning QR Codes.
It's scary to hear about malware that exfiltrates recovery phrases (seed phrases) from these images. That was my biggest fear and they really do exist. We should be very careful.