A trustworthy source IMO.

https://cks.nice.org.uk/topics/contraception-assessment/back...

The source you cite lacks an independent source for the Marquette model claims, and only single studies (cherry picked?) for the others. A recent Chochrane review states "the comparative efficacy of fertility awareness‐based methods for contraception remains unknown."

https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD...