I don’t see how landlord was in the wrong - They saw a package addressed for OP (the gift from mom) and then another package with the address but no name. It makes complete sense that they’d open that if they own/manage the condo.

The OP didn’t really fuck up either. Anyone has the right to order kinky shit in the mail to their home. The company fucked up by leaving the name off. Next time, perhaps OP could order something like that to the post office for personal pickup.