Asking this out of curiosity: is it a requirement, that such data is being stored once the verification process is completed?
in case of the EU it's more the opposite GDPR requires data minimalism and ~use case binding so if you submit data for age verification there is no technical reason to keep it after knowing your age so you _have to_ delete it.
The GDPR is your friend. It makes retailing unnecessary personal data a liability. As it should be.
Discord is idiotic for operating in the UK and Europe without complying.
No excuses.