https://www.reddit.com/settings/data-request
They must oblige within a certain time frame — even if your account has been suspended and I believe even if you’ve deleted your account. Curiously, this might be one effective way to protest. Golly I wonder what would happen if many people requested such reports simultaneously. It seems these must be processed manually by admins.
As a bonus, it’s nice because all your comments and messages are searchable.
Did you try requesting your data? I got my data within a day. They probably mention 30 days because that’s the legally defined deadline, and to give themselves some leeway in case the automated system has issues with some user.
It also makes sense for them to make it a low-priority task, as they have a really long deadline for it, and you don’t want it affecting the main site.