I filed for AOS for the first time in July 2020 when my July 09 priority date became current in FAD. My case is assigned to the national benefits center (MSC), and my field office is Boston, MA. It took several months to receive the biometrics appointment, but EAD/AP approvals followed soon after. Ever since, there has been no updates to the I-485 case status, which remains at the "Fingerprints were taken.." stage. Worse, the normal processing time--which at the time of filing the I-485 was between 8-24 months for Boston--has now increased to 13-52 months. And, its been about 8 months since I filed my I-485...
By now, I would've expected to (well, hoped to) see a change in status to "Case Under Review" or "Case being prepared for Interview". I did call USCIS' customer service today to inquire, but unsurprisingly, got nothing out of it.
I am considering writing to Liz Warren's office. I see Oct 09 priority date cases receiving interviews, and from what I can tell, my case would be considered pretty straight forward. Maybe I should say, I'd consider it straight forward

(Economist; been with the same firm for a while; medicals were filed with I-485). I guess it really benefits to have your case pre-adjudicated. I missed that opportunity.
Any thoughts on the best time to seek assistance from the Senator's office? A normal processing time of up to 52 months scares me to just sit on my a** in this continued perpetual wait.