If you have an expired visa, you can always come back to the US from Canada as long as you have an unexpired I-94 and the trip is <= 30 days. It's called Automatic Revalidation.
Source:
https://help.cbp.gov/s/article/Article-1218?language=en_US
https://travel.state.gov/content/travel/en/us-visas/visa-information-resources/visa-expiration-date/auto-revalidate.html
As for the non-essential travel thing, check this:
"On March 21, 2020, the U.S., Mexico, and Canada temporarily restricted non-essential travel across the
US-Canada land borders. On April 20, 2020, all parties agreed to extend the restrictions on non-essential travel across their shared borders for 30 additional days. We are maintaining cross-border activities with Canada and Mexico that support health security, trade, commerce, supply security, and other essential activities while taking critical steps to protect our citizens and to curb spread of the virus.
Does this apply to U.S. citizens and lawful permanent residents?
This restriction
does not apply to U.S. citizens, lawful permanent residents, persons from foreign countries who hold valid travel documents, and persons from foreign countries in the visa waiver program who are not otherwise subject to travel restrictions. This order does not apply to individual persons who should be excepted based on considerations of law enforcement, officer and public safety, humanitarian, or public health interests. "
Source:
https://help.cbp.gov/s/article/Article-1596?language=en_US