Yup ,Unfortunately NVC process is so behind, even more behind than their own time frame. USCIS to NVC at this moment takes around 30-40 days.
RFE usually has 90 days due date, however look like there is no time frame for USCIS to make decisions after RFER. Approval or denial are vary between 7 to 60 days after RFER.
Best thing is USCIS processing more case daily compare to 2-3 months ago, that will help reduce backlog somehow...
Only Positive thoughts and faith make this journey easier since USCIS process will stay a mystery.
Some day soon we all be with our loved ones