@Family suggested we send a letter to request a combo interview.
This is a letter I uploaded with wife's N-400 application. Did it help? I'm not sure. Did it hurt? , No. Absolutely Not!! Did we get a combo interview? Yes.
Our letter:
Wife Name
Address
August 7, 2022
US Citizenship & Immigration Services
P.O. Box 25920
Overland, KS 66225
Dear USCIS Officer
Please consider this letter as an official request for a combination I-751/N-400 interview or waiver of the I-751 interview. We submitted my joint I-751 petition in March of 2019. My biometrics was completed in May of 2019. The status of my I-751, case number MSC1XXXXXXXXX has been “Case is ready to be scheduled for an interview” since May 2019. I have received no RFEs or requests of any kind.
Sincerely,
Wife Signature
Name