Snakes don't all have the same personality: they don't all have the same genetics or the same life experiences, so why would you expect them to behave the same way? Be patient, have empathy- you'll figure out ways to help him settle in- mostly takes time.
You also mentioned this new snake is nearly a year old- many find that older snakes are MORE stressed by re-homing than young ones are. They've come to depend on their home environment- whereas hatchlings are like we were as little kids...pretty oblivious to many things, so they adapt with a bit less stress. Remember that snakes have NO clue as to how or why their entire world just changed (after being shipped, or taken home from a local store) so they may try to find their "home" for some time. Yes, when you understand what they're going thru, it feels pretty awful for them. Imagine yourself being abducted by aliens & carted off to a different world in a space ship, & you might have some idea what it feels like to be him.![]()