It's a long article so I don't expect you to find the argument in it; it highlights the work of Alina Chan who compared a fast mutation rate of SARS-CoV as it better adapted itself to human to SARS-CoV-2. Here are titles of three of them I've saved but not read, May through September of last year:
SARS-CoV-2 is well adapted for humans. What does this mean for re-emergence?
Single source of pangolin CoVs with a near identical Spike RBD to SARS-CoV-2
COVID-19 CG: Tracking SARS-CoV-2 mutations by locations and dates of interest