How to find out if I’m hacked

Click on this link "If you think your Apple ID has been compromised" --> https://support.apple.com/HT204145

'Checklist: If you want to see if anyone else has access to your device or accounts' click here --> https://support.apple.com/HT212021

Security and your Apple ID - https://support.apple.com/HT201303

Contact Apple for help with Apple ID account security - https://support.apple.com/HT204169 "This article provides country-specific Apple Support contact information for customers seeking help with their Apple ID password or other security-related issues." Better for directly reporting an issue.

Start by logging into your iCloud on the web and checking what and who has access to it. "Hacking" is basically impossible, but if someone or something has unauthorised access to your iCloud - then you can check and revoke. See Apple advice on hardening your iCloud account.

https://support.apple.com/en-gb/HT201303

Up to date iPhone? With iOS 14.8 or 15? Basically impossible to hack. Just follow standard security and hardening advice. If you are still really concerned you can always ask the Apple Store to do a reset - but that sounds like a lot of overkill.