The fight to me shows you can't just casually cut through them, and if you were to put your bodyweight into it, once the blade cut you'd slip most likely.
And Grievous was hit by some random gungan at the start of the fight, if that was one of the knights weapon's he'd probably be done.
The Knights were also able to move Kylo who is obviously strong in the force, pretty sure they could move Grievous easier. Six Padawans could probably take on Grievous yeah.
It was hard to tell exactly what was happening to their weapons in the film, because the scene was really fast/short, and also really dark.
But in The Rise of Kylo Ren, we saw their weapons fail multiple times against Luke's saber:
Now I suppose it's possible that the KoR made their weapons stronger after Luke raped them(it did look like they were at least able to block a few of Ben's strikes in the film), but as the VD states, they still weren't lightsaber-proof and could be cut through with a greater application of pressure. And given the fact that Grievous is also very strong physically, it seems likely that he would be able to cleave through their weaponry as well.
I’ve watched that scene multiple times and their weapons clearly block Kylo’s lightsaber.
Originally posted by Total Warrior
Lightsaber proof or not, Grevious is still mincing them. These guys were fodder, padawan tier likely. Do you think a bunch of padawans could take on Grevious?