not sure how to get the new achievement but I'm pretty sure the characters translate to "package returned" incase that helps anyone
use ender for a while
you need to put the endergirl in the box, the new bed, and put the engine at 2 or 3 and wait, like the backrooms achievement, but with the box and in the bamboo forest
It unlocks a new location for her
The trick is waiting for her to teleport away(You were right)