It's not really disputed that there were quaternary extinctions prior to the YD boundary, nor that megafauna survived for quite awhile after the boundary. There

It's not really disputed that there were quaternary extinctions prior to the YD boundary, nor that megafauna survived for quite awhile after the boundary. There's a whole wikipedia article on this, aptly titled 'Quaternary Extinction Event' [1]. [2] (from the supplemental data of [3] has a nice list in table 1. [1] https://en.wikipedia.org/wiki/Quaternary_extinction_event https://en.wikipedia.org/wiki/Quaternary_extinction_event [2] https://static-content.springer.com/esm/art%3A10.1038%2Fs41467-021-27439-6/MediaObjects/41467_2021_27439_MOESM1_ESM.pdf https://static-content.springer.com/esm/art%3A10.1038%2Fs414... [3] https://doi.org/10.1038/s41467-021-27439-6 https://doi.org/10.1038/s41467-021-27439-6