What are the authoritative sources you were told to use?  It's more a problem for someone who telecommutes from NJ for a NY employer than the other way around.

The governing sections are still NY Tax Law §620 and 20 CRR-NY 120.  Pay special attention to the section that deals with sourcing rules.

For good measure, here's the latest guidance in relation to COVID-19 from NY (which really doesn't say much): https://www.tax.ny.gov/pit/file/nonresident-faqs.htm#telecommuting