Potential double invoices code calculated column

Hello,

I've made a calculated column for checking if each rows invoice is potentially double invoice or a unique invoice. It should return duplicate if its double and unique if its a new invoice.

Only when I set this code in DAX in a calcuated column it gives me the error that you cant use countrows and filter in a calculated column?

Does anybody know why this code won't work and what the solution is?  

Thanks in advance.

Column = 
VAR varCurrentValue1 = 'EZK TRX_019_Overzicht_facturen_2023_DEV'[Zakenpartner_naam]
VAR varCurrentValue2 = 'EZK TRX_019_Overzicht_facturen_2023_DEV'[Datum_factuur]
VAR varCurrentValue3 = 'EZK TRX_019_Overzicht_facturen_2023_DEV'[Factuur_nr]
VAR varCurrentValue4 = 'EZK TRX_019_Overzicht_facturen_2023_DEV'[Bedrag_factuur_EV]
VAR varInstances = 
    COUNTROWS(
        FILTER(
            'EZK TRX_019_Overzicht_facturen_2023_DEV',
            'EZK TRX_019_Overzicht_facturen_2023_DEV'[Zakenpartner_naam] = varCurrentValue1 &&
            'EZK TRX_019_Overzicht_facturen_2023_DEV'[Datum_factuur] = varCurrentValue2 &&
            'EZK TRX_019_Overzicht_facturen_2023_DEV'[Factuur_nr] = varCurrentValue3 &&
            'EZK TRX_019_Overzicht_facturen_2023_DEV'[Bedrag_factuur_EV] = varCurrentValue4

        )
    )
var Result = 
    IF(
        varInstances > 1,
        "Duplicate",
        "Unique"
    )
RETURN
    Result