hi @cnapsys
Add urself a capsule component to the actor. Make it the root, then add your mesh as the child to that capsule.
Or in the Asset browser double click your mesh asset and it will open the editor for you to set more complex or accurate collisions for the actual mesh. then you could use it as a static mesh without being an actor if it doesnt need any interactivity. but looks like you want some explosiveness niceties going on so still, change the mesh collisions for hits, and if you need overlaps use the capsule component