Your approach to managing the number of BLOBs in your Azure BLOB storage by moving older files to an archive directory is reasonable and can help ensure you do not exceed the 10,000 file limit in the monitored directories. This method will help keep the number of files in the request_type_a and request_type_b directories manageable, which is important for performance and operational efficiency.

Regarding your question about changing older files to use the archive tier, it is important to note that the Azure BLOB storage account has a limit on the number of BLOBs per container, not specifically on the number of active or archived BLOBs. Therefore, moving files to the archive tier will not reduce the count of BLOBs in the container; it will only change their storage tier. The 10,000 BLOB limit applies to the total number of BLOBs in the container, regardless of their tier.