Just remember the purpose of rationalization. About a century ago they
said "Coulomb's law is used leess often than formulas derived from it.
That fundamental law does not have 4*PI in it but the factor does appear
in derived formulas, for example, C of a capacitor. Let us put 4*PI into
Coulomb's law and the factor will caancel out from the derived formulas."
This argument was valid when calculations were made by hand. The benefits
of mystifying Coulomb's law ("you will understand this later") are no
longer with us at the age of electronic calculators. You can play with
degrees of freedom but keep in mind that some approaches are conceptually
better than others. This is particulary true in introductory courses.
The old CGSE was logical in its simplicity, no borrowing from what will
be clear later was required. Justifying 4*PI*epsilon is practically
impossible without being dogmatic (just accept it because it is in the
textbook).