Been just linked to this post, that claims that on Lenny:

• Messages are never deleted, only hidden, a GDPR violation
• Deleted usernames are also not deleted, only hidden, same thing
• Stuff remains on federated servers even if you delete it
• There’s no way to delete yourself from the network if you choose to do so

Gut feeling says none of this is true or is only half truths, but want to be sure before i invest myself heavily on this platform.