They don't comply with GDPR. Not sure if it still works, but you can use PowerDeleteSuite to edit and then remove your comments. It's a good idea to keep your account open for another week or so to make sure Reddit doesn't restore deleted comments (they did for a few comments on my account), then delete the account in the preferences tab (I used old reddit to do so)
Do you think they would not delete my comments if I wanted them to delete everything according to the GDPR?
Because I could make a few test comments after deleting everything else(would be nice proof).
It might be naive of me to think that I can make a difference by reporting it, but I would love to see them get fined like Facebook/Meta recently did.
They (sometimes, from what I understand) claim that they cannot delete your commemt or post history, and will offer to delete your account while retaining the data.