If you disabled the account yourself, then you should be able to recover it and then press the delete button yourself. If it was disabled for a TOS violation or for legal reasons then they might have a gdpr exemption to deleting the data[0] (NAL).

As for messages, those aren’t deleted - while this might be legal (anonymization is seen as compliant with the right to be forgotten) they really should make it an option, otherwise people end up using scripts which do it for them[1].

0: https://ico.org.uk/for-organisations/guide-to-data-protectio...

1: https://github.com/victornpb/deleteDiscordMessages