and honestly, as someone who has done stick and weapon fighting, you 1000% accidentally bop yourself in the head from time to time. With blades you tend to be a lot more careful and the way you hold it can make it difficult for those bops to be dangerous, but a lightsaber is basically a sword that's all blade.
Isn't this one of the reasons the force is practically required to use a lightsaber? Just so you have perfect control at all times and do not cut yourself in two.
I suppose grievous is an exception, though an argument can be made that him being mostly mechanical allows him to not kill himself.
A lightsaber's blade is also lighter than a real blade, which would help mitigate the risk.
Though I could see boppin oneself in the face remaining a problem in this stance.
Do we know if Grievous had force sensitivity at all? Transplanted Jedi blood or horrendous insanity-inducing technology? Or is the robot body just a good enough mix of precise and expendable?
Back when he was Qymaen jai Sheelal, i'm certain I heard of him "carving out his connection" or something of the sort somewhere. So I think maybe a bit of mechanical precision and expendability is what kept him going after severing his connection with the force, which he previously used to train with a saber?