All anti virus apps for the iphone/ipad are basically worthless. Keep your iphone up to date 13.4.1 as of now, block ads in safari using a tool like adguard or another browser like Duckudckgo or Brave that has it built in, and finally encrypt and use a DNS that blocks malware and phishing my two reccomendations are 1.1.1.1 by Cloudflare or nextdns.io. These are all free and should keep you safe.