their younger counterparts [closed]

The sentence sounds good and natural, but your explanation misses a subtlety: a counterpart (in the definition that would be applicable here) is:

one having the same function or characteristics as another

The source is Merriam-Webster.

A native speaker familiar with the use of this word would probably assume that "counterparts" in the sentence you provided has a slightly more specific meaning than a repetition of the term "employee" would have - i.e a native speaker might assume that the younger "counterparts" are employees in the same field or having the same job descriptions as the elderly employees they are being compared to.