Distinct Count from filtered table by per category max value records.

Hi,
I am a novice to Power bi and expect your expertise assistance to solve below.
I have two tables, one is device data and the other is date table. Relationship between two tables is start date from device table and date from date table.

Device Table

If taking the user id 100001 to explain the logics to calculate ,

Final output should be like below table which Year and month is from date table.

(to get below table, always need to consider the record of maximum deviceTable[rank_date] for that particular user filtered first for considered date period)

1. Active users - 

distinct count of users, where deviceTable[start_date] <= endOfPeriod  && deviceTable[end_date] >= startOfPeriod, and if the deviceTable[device] = "x"

distinct count of users, where deviceTable[start_date] <= endOfPeriod  && deviceTable[end_date] >= startOfPeriod, and if the deviceTable[device] = "y"

Here the user's 100001 device "y" is active after 20/2/2020 his device "x" is no more considered as active as we always take the maximum deviceTable[rank_date] per user for the considered period.