Measure a work shift based on multiple datetime values

Hi community, 

I have been trying to create a formula using DAX that would calculate working shift hours based on "Index". The work shift starts when the first order is taken(Order Start) and ends when there's an interval of more than X hours between Order End and next Order Start or between Order Start and Last Order End, it doesn't really matter.

My last formula that I have created, which I will insert below, kind of worked but the problem is that it takes too long to load 10 000+ records.

VAR _orderDifference = DATEDIFF('Taxi Bolt'[Order DateTime Start], 'Taxi Bolt'[Order DateTime End],MINUTE)
VAR _lastDateTime = 
    CALCULATE(MAX( 'Taxi Bolt'[Order DateTime End] ),
        FILTER(
            'Taxi Bolt',
            DATEDIFF([Order DateTime End], EARLIER([Order DateTime End]), MINUTE) >= 0 &&
            'Taxi Bolt'[Index]=EARLIER([Index]) && 
            [Order DateTime End] <> EARLIER([Order DateTime End]
        ))
    )
    
VAR _betweenOrdersTime = DATEDIFF(_nextDateTime, 'Taxi Bolt'[Order DateTime Start],MINUTE)
VAR _total = _orderDifference + _betweenOrdersTime
return IF(_betweenOrdersTime > 120 , 0, _total )

Is anyone able to help me how to optimize this code or rewrite in the way that it will take faster to calculate and return the result?