Distinctcount and average per month

Hi Seb93 ,
Based on the information you provided, I have created some data hopefully to solve the problem for you. You can follow the steps below:
1. Add an index column.

2. Add some Columns.

Access = 
IF ( 'Table'[Device_category] = "Accessory", 1 )

Mac_Access = 
VAR _1 = 'Table'[Gateway_mac]
VAR _SumMac =
    CALCULATE (
        SUM ( 'Table'[Access] ),
        FILTER ( 'Table', 'Table'[Gateway_mac] = _1 )
    )
VAR _AccessMac =
    IF ( _SumMac >= 1, 1, 0 )
VAR _rank =
    RANKX (
        FILTER ( 'Table', 'Table'[Gateway_mac] = _1 ),
        'Table'[Index],
        ,
        ASC
    )
RETURN
    IF ( _AccessMac = _rank, 1, 0 )

3. Add some Measure.

CountMac = 
DISTINCTCOUNT ( 'Table'[Gateway_mac] )

FinalResult = 
DIVIDE ( SUM ( 'Table'[Mac_Access] ), [CountMac] )

Final output:

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If it does not help, please provide more details with your desired out put and pbix file without privacy information.

Best Regards,

Ada Wang

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