They hired administrative assistants from august till end of november and now they are hiring more until Feb 2022. Most likely those are to deal with temporary large backlog. They will most likely be doing grunt work like organizing files, stamping passports, and getting officers coffee, to leave analysts and officers available for reviewing and deciding on cases. The remaining hiring are until end of 2022 and early 2023. Those are most likely targeted for their future plans to immigration, relevant to increasing numbers of applications and changes to their IT.