On Earth, the cardinal directions are straightforward. The arrow on a compass points to the nearest magnetic pole. You can then use it to travel anywhere on Earth.
In space, the idea of anything being “central” enough to be used as a “North” (since the universe has no center) or being fixated enough to not somehow pose issues is more convoluted.
If you were a pioneer of space exploration, what would your “North” be?
If they’re intergalactic explorers, why would they care about the plane of our ordinary galaxy?
Why would they choose those 2 galaxies for a meridian?
Galactic coordinates are easy. OP asked about inter galactic.