help with tires

I have all seasons on my Chev 2019 Silverado. At an oil change the guy said my back tires were a "3". No way I was buying his tires but it begs the question...

What all season tires should I get? I do about 40km of highway driving in the winter, and a bunch in the summer if that matters.

Right now I'm not required to nor am I looking for winters