If you are caught midway, you get banned for abuse/ToS, and you are not allowed to delete/edit your comments-account if you are unable to sign in. (I am guessing they are retaining data under some bullshit about gdpr legitimate interest in preventing abuse)

Rate limits are also quite low so it might take weeks to delete. Many subs will automatically ban you if you edit a comment to say something like 'redacted by' (ex: https://www.reddit.com/r/ModSupport/comments/1t1fekj/redact_...)