T-Mobile insurance

T-Mobile Protestion <360> and AppleCare are two different protection plans.

See: https://www.t-mobile.com/support/devices/protectionandlt360andgt-and-device-protection

and

AppleCare Products - iPhone - Apple

You aren't required to have either of the above. You can have your iPhone repaired without either of those plans but it will be more expensive for eh repair. For example an iPhone 15 screen repair done by Apple in the U.S. is $279 without AppleCare+ but $29 if you have AppleCare+. See: iPhone Screen Repair - Apple Support

AppleCare is a service on its own. Your carrier may also offer different protection, but not needed by Apple to repair your device. Check with T-Mobile for the coverage of the service they offer, AppleCare is detailed in this Support Article:

AppleCare Products - Apple