I don’t have anything setup in front of me but you should be able to use a “Apply Radial Damage” or if you want it to have a falloff (Not be as strong on the outer edges of the damage radius) use a “Apply Radial Damage with Falloff” node.
In both of these you can set the base damage amount, the size of the radius, and the inner and outer radius if you’re using the falloff node. The base damage would at least need to be the amount of damage the DM would take unless you’re using accumulate damage in your DM for it to actually destroy.
Hopefully these will help you with a starting point for getting your grenade explosion going.
I am 1000% sure that apply radial damage is bugged. Iit sometimes does nothing, sometimes it hurts ine actor but leaves another untouched. Just watch recent 's stream where he was making a grenade, and he couldnt make the apply radial damage do anything. I said to him that I can never make it work.