Set range from target cell to xlDown until length of cell value in column is larger than 3 characters and finally Column Offset(-1, 0) for the range - excel

Question

I've defined a couple of ranges but have problems to define a new range with a few conditions. I'm trying to set a new range from target cell downwards until the length of first TRUE cell is larger than 3 characters. The new desired range would be "Range("C" & Target.Row & ":" & Range("C65536").End(xlDown).Address(0, 0))" but only for the for the cells that have 3 or less characters. The problem with that code is that it stops at the first non-empty cell. The final cell in the range would be the last cell with max 3 characters (and not empty) before a cell value has more than 3 characters.
For instance the new range would be C35:C47 which would then be applied for the adjacent cells as B35:B47. Later on in my code I would then use this new range (B35:B47) in a "for loop" to define new values for these adjacent cells.
Private Sub Worksheet_Change(ByVal Target As Range)
Dim r As Range
Dim rng As Range, cell As Range
Set rng = Range("B" & Target.Row & ":" & Range("B65536").End(xlUp).Address(0, 0))
Set r = Target
If Target.Column = 3 And Selection.Column = 3 Then
If Intersect(Range("C:C"), r) Is Nothing Then Exit Sub
If r.Value = "" Then Exit Sub
If r.Offset(0, 1).Value <> "" Then Exit Sub
If r.Offset(0, -1).Value <> "" Then Exit Sub
Application.EnableEvents = False
r.Offset(0, -1) = Application.WorksheetFunction.Max(Range("Sheet1!B7:B" & r.Row))
For Each cell In rng
If IsNumeric(cell.Value) Then
If cell.Value <> "" Then
cell.Value = cell.Value + 1
End If
Else
MsgBox "Cell " & cell.Address(0, 0) & " does not have a number"
Exit Sub
End If
Next
Application.EnableEvents = True
End If
End Sub
The new range would then be used in a similar way as the "for-loop" in the example with the difference that "rng" would be the new range --> "For Each cell in rng2"...