Lost about 1k keyword rankings in top 100 in 30 days

Just some backstory... My website was beginning to perform very well and started to gain a lot of Google impressions in September of 2021. I went from 2k impressions per day to 14k per day after adding new content to my site. Additionally, my keyword rankings in the top 100 went from under 1k to 1.8k in a few months. Fast forward to December 2021 and everything begins to sharply fall. My keyword rankings in the top 100 are dropping daily and I'm now at 900 total. My Google impressions are also dropping daily and I've gone from 14k to 5k in a matter of weeks. I don't know why this is happening. The only thing I can think of is a penalty for duplicating city pages on my site in an attempt to rank in other cities. I intended to make unique content for each page but ultimately removed the pages to see if it would stop the slowdown. Any thoughts?