Will doing a factory reset remove malware

That's almost certainly not a malware issue. Try just restarting it, if you haven't done so already. Then if that doesn't help, and updating to iOS 18.1, just released today, doesn't help either, then restoring to factory settings might fix it. If you do try restoring, I'd first suggest that you restore without using a backup, just in case there's a corruption in a background file that would come back from the backup, and work with the iPhone for a while and see if the problem is corrected. If it is, then you can if you wish try restoring using a backup.

Regards.

It's highly unlikely that your iPhone has malware on it unless your phone has been jailbroken. What leads you to think that yours might be infected?