This seems to do it all, very slow, and test on a sample book - not original.
Sub combineAccounts()
Dim x, lr As Long
Dim ws As Worksheet
Dim aPtype As Variant

Application.ScreenUpdating = False

Set ws = Worksheets("S1-var")
    
    With ws
        lr = .Cells(Rows.Count, "A").End(xlUp).Row
        
        For x = lr To 3 Step -1
            Set pFnd = .Range("I1:DE1").Find(Left(Cells(x, "EC"), Len(Cells(x, "EC")) - 3), , Excel.xlValues)
            pFnd.Offset(x - 1).Value = Cells(x, 2).Value
        Next x
        
        For r = lr To 3 Step -1
            For c = 10 To 109
                If .Cells(r, "E") = .Cells(r - 1, "E") And _
                    Cells(r - 1, c).Value = "" Then
                    Cells(r, c).Copy Cells(r - 1, c)
                    Cells(r, "D").Value = "To Delete"
                ElseIf .Cells(r, "E") = .Cells(r - 1, "E") And _
                    Cells(r - 1, c).Value <> "" Then
                    Cells(r, c).Copy Cells(r - 1, c + 1)
                    Cells(r, "D").Value = "To Delete"
                   
                End If
            Next c
        Next r
    
        For d = lr To 3 Step -1
            If Cells(d, "D").Value = "To Delete" Then
            Cells(d, "D").EntireRow.Delete
            End If
        Next d
    
    End With
        
    Application.ScreenUpdating = True

End Sub
vbax52868d.xlsm