Yes, they are next level noisy. Enough that you may want to warn your neighbors ahead of time if you use it outside

The one I have is big and the grinder is also pretty heavy so you do have to hold it tight and pay attention. I don't think they will catch anything and go crazy and fly out of your hands, but they do have a gyroscopic effect that you have to pay attention to You'll want to wear gloves and watch your knuckles too as they are right above the edge of the disc. Basically treat it like a chainsaw or any serious tool that could harm you and you'll be ok.

They do sell smaller diameter ones that mount to the smaller angle grinders and that may be easier and cheaper to try out first. The grinder I have is construction site sized so I bought a used one at a pawn shop.