Although I'm not a corned beef and (especially) cabbage fan, I made some yesterday for my inlaws.
Feature this - a 3 lb. brisket, frozen. It's 2:00pm. Threw it, frozen, into the Instapot for 102 minutes. Perfect!
Learned something new! The ability of the Instapot to cook from frozen (basically just needs a bit more time) was a revelation.