No, this Sad Bastard can attest that it is relevant, but the issues you bring up do complicate matters by no small degree.I'm not even sure how to respond to this. The ring was completely new technology. Huyang commented on its immensity. They weren't just traveling to some uncharted star, but to an entirely different galaxy. Several orders of magnitude farther away. None of the stuff you said is relevant.
Even within the GFFA, there is a tangled knot of hyperspatial anomalies spinward of Coruscant, which is why the following map shows that most exploration went into what was popularly known as "The Slice" and moved spinward and trailing from the major hyperlanes (Perlemian Route and Corellian Run) that bounded said area.
We knew from Episode V and Episode II that the GFFA has satellite galaxies. From Wookieepedia:
The galaxy was orbited by seven dwarf satellite galaxies, some of which contained twenty billion stars. They were ranked in order of distance. The closest was Companion Aurek, also known as the Rishi Maze, a complex tangle of stars high above the galactic plane. Companion Besh, also known as Firefist, was some 150,000 light-years away from the galaxy and had only ever been surveyed by probots. The other satellite galaxies, Companions Cresh through Grek, were much further out. Most of the Companions were described as having ancient, metal-poor remnants of stars and not much life.
Hyperspace travel is affected by mass -- planetary masses and stellar masses. As far as I know, very few studies have been done as to how galactic scale masses affect matters, but if my memory is accurate, trans-galactic travel is technically a thing during the movie saga period.
(I recall that Leland Chee had said that the Haven rendezvous point for the Alliance forces fleeing Hoth at the end of Episode V is within view of the Rishi Maze, and I believe the Essential Atlas placed Kamino within said satellite galaxy as well. Companion Besh will be known to Marvel SW readers as the home of the Nagai and Tof species.)
So, this ring may be something that the Celestials (or perhaps another outfit) were using to link the systems together more easily, perhaps overcome the galactic-scale tangles and gravitic eddies that make such travel several orders of magnitude harder than even the Deep Core region (which usually required either S-thread boosters to keep routes stable or monthly navicomputer updates.
Of course, it could be even further. No-one's really infodumped the astrogation data, so we have no real way of knowing where an unknown technology put them.
But if we are dealing with one of the dwarf satellite galaxies, a telescope and sextant will be of some use, and a Class 1 hyperdrive will (eventually, and with likely a lot of small jumps in case the Intergalactic Void isn't quite empty.... ) get them back.... though it won't be anything like flying a crop-dusting airspeeder.