Or an upcasted scry stoneskin telport etc using their strongholdThat how I read it to. It’s an interesting gamble, throw down a 9th level fireball with a DC 19 check,
if we assume 20 int and advantage on the check, that’s 51% check. I’d say that’s a generally a gamble not worth taking, but I could see an adventurous party giving it a shot.
All in all not OP to me, seems a high gamble to get such a benefit
