Security updates
Is it necessary to download latest security update patches if it doesn’t apply to features on my device?
iPhone 12 mini
Question marked as
Keep the iPhone updated to the latest iOS always. That's it.
iOS / iPadOS devices cannot be infected with Virus / Malware / Spyware if it is updated to the latest iOS/iPadOS unless you have intentionally downloaded spurious software or unauthorized apps directly from the internet and installed them on your device.