Thank you mom and others who answered my questions during the daunting wait period.I noticed your update on the Timeline Spreadsheet with the interview being waived. Congratulations.
FYI: I submitted a congressional inquiry and this was my experience: The congressperson's staff called me back the same day after I submitted the online request form. They asked me to sign the USCIS privacy release form and email it back to them. I explained that my case had been pending for nearly six months without any updates. Although they mentioned that I might not qualify for an expedite request based on USCIS's criteria, they said they would help me so I gave them my DV selection letter, DV fee receipt, and my I485 receipts as supporting documents. I explained that DV cases are given priority due to numerical limitations and must be adjudicated within the relevant fiscal year. I also stressed the risk of visa exhaustion or timing out. To my surprise, my case was approved two days later. However, I cannot definitively confirm whether the inquiry directly led to the adjudication by USCIS. Best of luck to everyone!