VBA data validation, dependent dropdown list

Hi everyone,

I'm working on an excel that consists of a fill-in form within the worksheet. I understand it may be better to use a userform and activeXcontrols, but I already have 2 userform in the workbook.
*The workbook needs to be usable by all users, therefore I can't use plug-ins.
*I'm totally new in VBA, so please avoid "refer to this link" only. I won't be able to understand the code unless it has comments. I need to know where and which part I can/cannot change.

I need to generate a dependent dropdown list. Which I managed to have it working, however, (as attached) I need to place the reference value in Cell M2. Is there possibly a method to not having to display a value in cell M2 and still have it working?

Notes:
1. information of column [F, G] and [I,J,K] is not constant, as user can add new "company", "product", "detail" to list
2. the actual lists is separated into different worksheet (ie. sheet1 = in-sheet form, sheet2 = company list, sheet 3 = product list)
3. reason that I'm doing this in VBA and not excel built-in functions is to avoid formula loss (overwriting the data without realizing it and then saving the workbook [which happened before])

Possible Error:
I realized that if the list from column I to K is not sorted according to column I, the drop down list will generate mismatch

For example
Col I Col J
A apple
A orange
B Beef
A Lemon

with this list above, the dependent drop down list for A will be (apple, orange, BEEF). It can count there are 3 "A" but the results are shifted.

I appreciate for your help!

Private Sub Worksheet_Change(ByVal Target As Range)

    Dim selected_company As String
    
    With Worksheet("sheet1")
        If .Range("a2") = Empty Then
            .Range("b2,c2,m2") = Empty
            Exit Sub
        Else
            selected_company = Application.WorksheetFunction.VLookup(.Range("A2"), .Range("F:G"), 2, False)
                
            With .Range("B2").Validation
                .Delete
                .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:= _
                xlBetween, Formula1:= _
                "=OFFSET(OFFSET(I:I,0,1,1,1),MATCH(M2,I:I,0)-1,0,COUNTIF(I:I,M2))"
                'perheps i can replace M2 with selected_company, but as I have tried it didn't work
            End With
        End If
    End With

End Sub