How do I achieve pseudo-anonymous postal mail?

That something I’ve used in the past (Postal Customer) and it’s pretty great. Unfortunately this PMB situation - without giving too much information away. This shop has delivered mail of previous customers to my box. I don’t know if this is the result of lack of enforcement or a true mistake. These were also paper letters - a package might trigger more scrutiny. For my use case, reliably getting my stuff trumps ultimate privacy.