Fellow Nashvillian - had the same panic yesterday and ordered some Dithiopyr: https://www.amazon.com/gp/product/B08DKD7V6K

Was worried about the delivery date, but shipper got the order onto FEDEX today with a delivery date of tomorrow.

My hope is that the upcoming cooldown tomorrow might slow everything down a bit, but I'm going to use the weekend at the latest to put down my herbicide.