Looks like the canon response (Hidalgo) is the planet moves though. Very small planet? Massive hyperdrive that overcomes the gravity well imposed by the planet itself? New discovery that if the hyperdrive is protected by powerful shields and sunk into the core of the planet it can avoid the negation of the planet's gravity well?
Is there a source within the movies that actually causes hyperdrives to not work within gravity wells though? I understand that a history of novels and information has built hyperdrives to not work within a gravity well, but with the new cannon being the movies, clone wars, rebels, and books after the cut being the only actual cannon, what says that a gravity well would stop a hyperdrive? Han jumped straight into the atmosphere of the planet regardless of it's gravity well. This could very well be one of those "you must unlearn what you have learned" moments. I'm trying to remember something within the new cannon that would stop something like a planet being mobile.
Could they somehow have "turned off" the gravity well of the base? I know it is a planet, but maybe it has lost some of its planet qualities with all the new technology and kyber crystals/force-stuff(?) and turning it into a base and all.
Would it have to be in orbit of the star/sun of the system it is in? This is space opera after all, anything is possible... They didn`t turn the planet into a base, they turned it into a ship, an actual STAR DESTROYER!
I'm not trying to argue or disagree, but I'm honestly asking if there is anything in the new cannon that stops hypderives from working within gravity wells. As far as I know that piece of tech trivia died with the cannon reset. Perhaps now you can just slap a big enough hyperdrive on a planet and go toddling around the galaxy or jump straight into the atmosphere with a light freighter. I think we've seen interdictors in rebels, but for all we know they put out a hyperdrive interference signal that causes hyperdrives do an emergency stop.
Consider this quote from Han, bolded emphasis is mine:"Traveling through hyperspace ain't like dusting crops, boy! Without precise calculations we could fly right through a star , or bounce too close to a supernova and that'd end your trip real quick, wouldn't it."
This implies that without the right coordinates you could go right through a star. That, to me, implies a lot of what we have taken for granted about hyperdrives and gravity wells doesn't actually exist outside WEG and possibly some older books.