Email validation is completely different from email verification.
Validation only checks the email pattern, i.e. if the text contains @ and .
What you are asking for is email verification, which is something that Wix does not provide. Wix only validates the email, and if the pattern is correct, then considers it as a legitimate email.
If you want to implement email verification, you can either have a unique code sent to that email which the user has to manually enter in order to verify the email, or you can use APIs that can determine the deliverability of the entered email address.
Coding such logic takes time, lets hope there’s a dev who ‘feels free’ to give you a ready code that you can copy paste…