But the runes do exist in Forgotten Realms. The only problem here that normally they require you to cast a certain spell. And once upon a time in NWN this exact problem was simply solved by granting the player homebrewed teleportation stone and some another homebrew artifact in SotU. Larian here could apply same exact solution through some small quest or giving us the artifact on naughtoloid.
A single line could be added to Gale's introduction: "I found this stone in the wreckage of the nautiloid; it seems to light up when brought near these runes."
Either these runes could be the general Teleportation Circles that exist in Forgotten Realms, or they could be some specific Absolute-related creation that you have gained access to through stealing/recovering this magic stone. Either option aids immersion, and the latter option could be relevant to the story-at-large.
