Per an article posted by Forbes, the new Fallout 76 scrapboxes and private worlds aren't functioning as planned. Forbes reports that scapboxes are deleting people's scrap and the "private worlds," which are supposed to spawn a fresh instance of the FO76 world, are appearing to be old/played through instances.
So, not only is your $13 a month not getting you a truly private server, but now you are literally paying Bethesda to destroy the in-game items you worked hard to farm and find. It's just comical at this point.
I think it's safe to issue a "buyer beware" on all Bethesda products for the foreseeable future. Bethesda has a lot of work to do to show that their future games aren't just about making a quick buck and leaving the player base in the dust. Good luck to them.
Forbes article: https://www.forbes.com/sites/paultassi/2019/10/24/fallout-76s-premium-private-servers-are-not-private-its-scrap-box-is-deleting-scrap/#55207c773863