How do I delete any remote management app on iPhone?

If someone else had your iPhone passcode and had physical access to your iPhone, and signed you out of your iPhone iCloud and signed themselves in, or if someone else physically connected a Mac running Xcode to and hen enabled Developer Mode, or loaded third-party apps or such, that would be a significant security breach. That would be a catastrophic breach, if their intent was hostile.

Given the scope of what can be viewed and changed here, your options here are limited to restoring a backup created from prior to that login, or to resetting the iPhone and starting over.

Starting over includes setting a new device passcode, setting new passwords everywhere, and re-setting biometrics (Touch ID, Face ID) if you are using those, as whoever reset your device can have all of your saved passwords and can add themselves to your biometric.

What particularly are you referring to as “coding and stuff root this and that”?

And there is no known remote management, absent user interaction, or espionage-grade exploit tooling, or a compromised passcode and/or Apple ID.