For me the function I passed you worked fine, but I guess you have a more complex table than the one I tried and eventually the values repeat, which does not permit it to "aggregate" as unique values.
If you woud add a "max" it would probably bring you the correct answer, such as:
=FirstSortedValue( sub_name, aggr(-(Max(Value+sub_name/10000)), sub_name)) &' - '& max(Value)
Just one thing I noticed about the answer marked as correct is that it may bring you the wrong result if the sub_name is between 0 to 9, for exemple, I tested with the following inline and the result was a bit misleading
LOAD * INLINE [
You can adjust that doing