VBA - Trying to use For / Next Loop macro to go to next dynamic cell range in column 'C'

Currently I have the macro selecting the first active cell range within column C, looks at the value in the first cell, then copies the value to all the remaining cells in that range.
The problem I'm having is how to properly go to the next cell range to perform the same task for the next active cell range...and so on until end of active cells in column 'C'.
I've tried using a for loop, but am having no luck(removed from code to remove confusion).
Any help would be appreciated.

Thanks in advance.

Sub Macro4()
    
    Range("C1").Select 
    Selection.End(xlDown).Select 
    
    ActiveCell.CurrentRegion.Rows(2).Select
    
    Range(Selection, Selection.End(xlDown)).Select
    
    Selection.FormulaR1C1 = "=R[-1]C"
            
End Sub