Thanks for showing the world how little expertise you have. AppleCare, security experts, tech writers, etc. will tell you that if you have not jailbroken your iPhone, you don’t share your Apple ID, have a strong password for it and a good passcode on your iPhone then no one can remotely change the settings on your iPhone. And no, the operating systems for the iPhone and Windows are very different so that is an inapt comparison. You can get SMS text messages from any cell phone that has a cell voice connection, no data or WiFi connection is required. And “secure” depends on a lot of issues not the least of which is the cost of the intrusion. What is on your iPhone that someone would spend millions of dollars to get?
As far as work if you are using a work iPhone, whether it be personal or work issued, they can put profiles on your iPhone that will override some things you try to do, such as turning off location services and find my. And if you are in the US it is NOT against the law to go through employees personal items. And IP addresses are public, getting someone’s IP address is easy and not illegal but it doesn’t harm anyone either.