How would it overlap or differ from 'Statistical Rethinking'?

This is widely regarded as the most accessible intro textbook to Bayesian statistics.

https://xcelab.net/rm/

+ Krushke’s Doing Bayesian Data Analysis, and for the very basics there is Downey’s Think Bayes. I guess there might be a gap in the literature for a different approach, heck, I’d read it, but there is some very good material already out there.