If your end user uploads a media using a Flow where KYC was enforced, that means they also successfully passed ID verification as otherwise they wouldn't be allowed to do so.
Not only that, SnapCall leaves a private note on the ticket which confirms that the ID verification has been successful, as shown below.
If you're using a Flow on a bot instead, you will also be able to get the confirmation of the KYC process via SnapCall metadata.