Spyware

Most likely a phishing attempt and you should not provide any information about your account. These emails are common on any platform. If you have provided your Apple ID password, then it must be reset.

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

Change your Apple ID password - Apple Support

If your Apple ID has been compromised:

If you think your Apple ID has been compromised - Apple Support

You can also perform the Safety Check on your device to review any other devices signed into your account and see if you are sharing data inadvertently.

How Safety Check on iPhone works to keep you safe - Apple Support

It's a scam. Ignore and delete.

The entire purpose of Pegasus is to secretly spy on high profile targets. It would be the exact opposite of the purpose to tell you you're infected.

This came from myself to myself!!!

I get those at least a few times a week. Usually the same tired scam of claiming to have videos of me doing something naughty. But oh!, if I send some random amount of money to a Bitcoin account, they promise to delete them.