Sorry. Not even remotely true. That said I freely admit his tenure here was abysmal, just not top 10 historically bad.
What I think you're referring to is that CDA was the 3rd worst
active coach at the beginning of this season. He was succeeded at "worstness" (chuckle) by Eberflous and Gannon to start the year (see link 1).
But there have been many worse than him throughout NFL history. I don't want to do the work to see where he actually lands but link 2 shows the worst 13, by record, in real NFL history and CDA isn't on the list.
1.
https://www.sportsgrid.com/nfl/article/worst-records-of-active-nfl-head-coaches
2.
https://touchdownwire.usatoday.com/lists/worst-coaches-nfl-history