Malware on iPhone

I know I have read many things that have stated that it is rare for iPhones to get viruses or malware, unless you have a jailbroken phone or download something from the internet. Unfortunately, I accidentally clicked on an email link and downloaded the file on my iPhone. So my question is how do I determine if my phone has been infected with malware and how do I remove it if so. I have done all the recommended steps like clearing browser history, removing any suspicious/old apps, ios is up to date, restarted the phone. However, I am still noticing that my battery usage seems to be going down faster than normal (I did check my battery usage in settings and I don't see anything abnormal but it doesn't change that my battery draining faster than normal). I was trying to avoid a factory reset or restoring from backup as my last backup was about 6 months ago, but I am seriously considering it just to be sure that I don't have any hidden problems. From what I have read, while malware is rare it can happen, and if it does it is likely sophisticated enough that it would be hard to detect. I am hoping that someone has some other steps to consider to clean up any potential problems. Any help would be appreciated.