The Holdo maneuver blatantly breaks canon. And I’m not just talking about some little detail from a comic book. I’m talking about things that are established in the previous seven movies.
When a ship goes into “light speed”, it is actually traveling through hyperspace, which is another pathway outside of space that allows a travel time which would equate to faster than the speed of light. The ship isn’t actually traveling at that speed.
With that being said, Holdo’s ship would not have been able to collide with the First Order ships. It would have been traveling outside of space. The only defense I’ve heard for it is “so what, it looked cool.” These people are completely ignoring all implications this has for Star Wars. Why didn’t they use this maneuver on the Death Star? Take one x-wing, have a droid pilot it, and just aim at the Death Star. This isn’t exactly a brilliant plan. At that point in the timeline. Armies would just be firing light speed missiles at each other’s planets. It kind of takes the magic out of the other movies for me.