The Evidence COVID-19 Was Spreading Around the World in Late 2019
On this evidence it seems we can definitively rule out both an emergence before July 2019 (too many negatives and just one questionable positive) and after November 2019 (too many positives in a number of countries). The evidence is not currently consistent or robust enough to be able to pin it down more definitively than that.
The Evidence COVID-19 Was Spreading Around the World in Late 2019 Read Journal Article