They have warned about this before, but it’s still pretty wild to think they’re now removing old DMs (and chats, but it’s not like anyone used those).
Interestingly you can still see them if you take out your data via a request, so they got them in the database still.
Looking at you YouTube, deleting videos and removing any trace of them from my playlists. Sad that you got to download so much these days or it’s just gone because a pixel or a single audio nanosecond will get it flagged and deleted.