You could try using a switch on string or switch on name. Say “if name is equal to this name then set the static mesh to be this one.” Strings and static meshes are completely different entities, so while you can convert an mesh’s name to string, you can’t convert a string to a mesh.
You might also create an array of these static meshes and when you need to get one of them with the string name, do a foreach loop on the array and “Get display name” of each array element, then if the display name == the string you can break out of the loop and use that array element.