Bdsp thief tm

Got a Murrow with super luck was going to teach it thief to farm some held items, apparently must’ve used the tm from eterna city at some point earlier in my play through, what’s the easiest way to get thief on this Murrow? Scoured the underground venders but no dice. If I start a new play through under a different account on my switch can I then use home to transfer the Murkrow around and teach it thief via the eterna city tm in the new play through and then bring it back? Or is there an easier way and I’m over thinking this?