How do I recover my forgotten iPhone password?

Passcode to the device or Password to your account?

If you forgot your Apple Account Password:

If you forgot your Apple Account password - Apple Support

If you forgot your Device Passcode:

If you forgot your iPhone passcode or your iPhone is disabled - Apple Support

I can’t forget what I never knew.

Re: “… I can’t forget what I never knew …”

Actually a concept in “phishing-resistant” authentication (e.g. Passkeys) !!! 😉