Find unauthorised third parties accessing my iPhone
Someone has unauthorised access to my phone and changing passwords doesn’t help as I believe the new data goes straight to the third party
iPad, iPadOS 16
Nope, not possible. You can change your iCloud password if you think someone has compromised the password. And, be sure to enable two-factor authentication. If you think your Apple Account has been compromised - Apple Support
You can also see all devices attached to your account at appleid.apple.com