> can you prove in court you received a given email? No, because a SSL connection is transient and you can't replay it to show that Google's certificate digitally signed that email in GMail.
A TLS session replay is unnecessary. If you've got the email with its headers intact then you can prove that you received that email.
You might want to learn what email headers are available to you. You'd be interested in learning about ARC-Seal, ARC-Message-Signature, ARC-Authentication-Results, and DKIM-Signature. Those headers will let you cryptographically validate that a message is authentic -- that the email is unaltered as Google received it from whoever sent it.
You'll also be interested in learning about Key Transparency: the signatures are created using Google's PKI which should be listed in any public key transparency log. That will let you prove that the signatures you validated were created using something that only Google knows.
A TLS session replay is unnecessary. If you've got the email with its headers intact then you can prove that you received that email.
You might want to learn what email headers are available to you. You'd be interested in learning about ARC-Seal, ARC-Message-Signature, ARC-Authentication-Results, and DKIM-Signature. Those headers will let you cryptographically validate that a message is authentic -- that the email is unaltered as Google received it from whoever sent it.
You'll also be interested in learning about Key Transparency: the signatures are created using Google's PKI which should be listed in any public key transparency log. That will let you prove that the signatures you validated were created using something that only Google knows.