To answer your question. Each petition are processed as separate, individual petitions. The I-400 was processed according to its rules and regulations that do not pertain to I-751.
This is why we tell people that there is no such thing as a combo interview. Your local office does not have to do it. Until that has processed citizenship is on hold or supervisor will deny and you will have to refile after I-751 is approved. Also you cannot appeal the denial.
So you filed for I-751 in December2021 and filed for I-400 in April 2021.
When is your 2 year expiration date? Why did you file for I-400 before I-751?