Each case is diferent, my cousin sent his application on april 8 , 2020 and got a RFE on january 2022, he sent evidences on february 28, 2022 . Uscis updated his case as evidence received march 10, 2022 , after that he hasnβt hear anything from them.
more that 90 days from when he sent evidence and 2 years and 2 months from the time he sent his i-751. Still waiting