GetDataTableRow outputs a specific type of struct, so changing the type of DataTable with a variable at runtime, would also change the type of struct it outputs, which would break its connection to the BreakStruct node.
it would be nice if GetDataTableRow just output a blob of Bytes in binary, and we could cast that blob to a specific struct, but structs don’t allow casting or inheritance to make them as light weight as possible.
since UE4 doesn’t have struct inheritance and struct casting, you should design data tables to hold data for categories of generic functionality, rather than specific objects. so you can have a weapons data table, but you shouldn’t have a shotgun data table, shotgun should be just a row, not a table. each type of enemy should not have its own data table, they should each be a row in an Enemies data table.