Firmware Integrity

More than a year ago, I asked if it could be possible that I could have my iPhone firmware content verified by Apple to be unchanged and unmodified by any “threat actor.” I am NOT talking about any change to my firmware that would result from myself downloading apps from sources outside the Apple Store, or intentionally trying to jailbreak my device. I AM talking about any malware which might be able to result from a threat actor somehow gaining kernel access with system administrator privileges - such as what might occur previous to the LATEST iOS update to 15.2, or what might also have been accomplished using the latest log4shell vulnerability in Java. I was told that Apple devices “never get any viruses or malware.” Doesn’t someone think that it’s about time to be getting honest - firmware and iOS security (along with iCloud security) are ALL JOB #1 at Apple, or should be! I want to know if there is a way that the current integrity if my iPhone could be periodically checked!! Would I have to bring my device into an Apple Store to do that, OR could it be done online via WiFi at my home or at work, OR would this currently be a precautionary measure which is simply not available to the Apple customers??