How can I check if my iPhone is compromised?

Your phone is not hacked unless you let someone else use it for an hour or so and also provided them with your Apple ID and Password.

If you are still not convinced, run Safety Check on your iPhone.

Safety Check for an iPhone with iOS 16 or later - Apple Support

What makes you think your iPhone is compromised? Just because you don’t understand how it’s behaving, doesn’t mean it’s hacked. The odds of your iPhone being hacked are nearly impossible, the only way being jail breaking, whereas stated someone must physically have your iPhone for some time.

Perhaps you can tell us what you don’t understand about your iPhone, and we can assist you.