Macro for conditional formatting bottom border

do you mean this?

Sub test()
    
Dim rng As Range, sh As Worksheet, breaks_count As Long, i As Long
 
Set sh = ActiveSheet

sh.Range("a" & sh.ListObjects(1).ListRows.Count).Activate

breaks_count = sh.HPageBreaks.Count

For i = 1 To breaks_count
    If rng Is Nothing Then Set rng = sh.Range("B" & sh.HPageBreaks(i).Location.Row - 1).Resize(, 7) Else Set rng = Union(sh.Range("B" & sh.HPageBreaks(i).Location.Row - 1).Resize(, 7), rng)
Next
    
If Not rng Is Nothing Then rng.Borders(xlEdgeBottom).LineStyle = xlContinuous
    
End Sub