Count Unique Reference number based on Monthly data / date created and resolved date

Hi! I'm hoping someone would be able to assist me. I'm trying to create a formula that will calculate the number of unique reference numbers I have on a monthly basis.

The conditions should be:  For the Month of January 2023.

1. Calculate the number of unique reference, Column A. If Date Created is on or after =<31/01/2023, where resolved date is blank or or have a resolved date after 31/01/2023.  I will need this on a monthly basis, so data for February, March onwards. 

2. Then I need the same as above condition, but to  only return items by Data Source 1 and LOB 2.

Hi! I'm hoping someone would be able to assist me. I'm trying to create a formula that will calculate the number of unique reference numbers I have on a monthly basis.

The conditions should be:  For the Month of January 2023.

1. Calculate the number of unique reference, Column A. If Date Created is on or after =<31/01/2023, where resolved date is blank or or have a resolved date after 31/01/2023.  I will need this on a monthly basis, so data for February, March onwards. Performing trending analysis.

2. Then I need the same as above condition, but to  only return items by Data Source 1 and LOB 2.

Any guidance would be much appreciated.