Okay, or at least not a plot hole that Rian created.
So, the hyperspace bit, with crashing the Raddus into the Supremacy. I'm seeing some stuff that this is some kind of game-breaking glitch, or in movie-speak, major plot hole, and like... no? Or, if it is, it isn't RIAN'S plot hole, but but the original franchise's one.
Basically some people I guess are saying that if you can crash into things at light speed, why hasn't anyone ever done it before, to end the battle? And yeah, GOOD QUESTION. Why hasn't anyone? But Rian didn't write the previous films, so why are people laying this at the door of The Last Jedi?
And you can't say that it's because it was just never possible in the SW universe before, because crashing into things in hyperdrive was never off the table. Doesn't Han mention something early on about how dangerous it would be to crash in hyperdrive? (Although I might be wrong on that or misremembering?) So it's a thing that could happen, although you wouldn't want to do it unless you were desperate.
So yeah, what would even be the need for a death star? The Empire (or First Order) could have just gotten some Stormtroopers to crash ships into the planets they wanted gone, and there would be no room for niggling things like "waiting for it to warm up" or get built, or fatal design flaws. There would be no time for anything.
So yeah, a plot hole? But not Rian's plot hole. All TLJ did was highlight a flaw in previous movies.
(I'm not getting into real life science here with mass increasing as you get closer to light speed etc. because SW never does, so why bother.