Is my iPhone hacked?

Restore using iTunes to get a fresh copy of iOS.

Here's how to restore your phone. Follow the iTunes section.

If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

Set up as new to "break" the chain from your old configuration.

New iOS and no old apps = new start.

The various scanners in the App Store (like syssecinfo in the German App store) that claim to detect a Pegasus jailbreak are notorious for high false positive results. I would not beleive anything they may turn up.

You won't get help here if your iPhone is jailbroken.

Read this: Unauthorized modification of iOS can cause security vulnerabilities, instability, shortened battery life, and other issu…

Hello,

If your iPhone is jailbroken it's possible. As jailbreaking removes the security features built into iOS.

With stock iOS there is no way to get hacked.

I wouldn't worry about it. Just make sure you keep your iPhone up to date.

As Michael said the app is probably false. Along with any other apps.