iPhone 16 Plus hacked via bluejacking or Playground game

Do you have anything installed at Settings > General > VPN & Device Management?

If you have a Developer Certificate installed to add a game without using the App Store, remove it and report back what they were. If any of your accounts were compromised previously, they are still going to be compromised with a new device. That is no indication of a root issue.

With any app problems, delete it and download again from the App Store. All data for that app will be removed from the device including any corrupted data files.

As noted by other posters, the likelihood that your phone has been compromised is almost zero.

If you describe the problems you're seeing in more detail, though, it's likely that someone can help you figure out what's really wrong. If you're seeing problems persist after getting a new phone, it's likely that the issues were transferred when you migrated your data.

Also, update to iOS 18.6.

Nope. Your phone was not hacked.

Try actually explaining what's wrong.

If you feel an unauthorized person/app is remotely using, controlling or monitoring your device, then that is possible only if you have done one or more of the following Don'ts...

1. Don't hand over an iPhone to kids or to a stranger without Enabling Guided Access
2. Don't share Apple IDs
3. Don't Jailbreak
4. Don't share sensitive information pertaining to your device
5. Don't give in to Phishing
6. Don't plug in your device in Airports and Public places through third-party cables and trust the device. Beware of Juice Jacking. (Especially in India)
7. Don't leave your iPhone unlocked and unattended in public places like offices, schools, malls, etc.

If one of the above is true then quickly change the Apple ID Password and Return iPhone settings to their defaults.

Your iPhone has not been hacked.