Please excuse my boldness. You are not a cautious driver.The tire guy is an “idiot”.
What you look for in protection from black ice you now increase you chance of accident in ALL traction situations because of tire traction imbalance. You have put tires with the best traction on snow/ice on front and the best traction on pavement on the rear (loss of front braking traction). Your car is an accident waiting to happen. This is especially so when studs are new.
I would recommend you go somewhere else and purchase a top brand studless winter tire (Nokian example) as the newer brands approach studded for all but the most sever conditions without the potential loss of traction you can suffer on dry pavement.
I was always a huge fan of studded tires until the last few years as I have a daily need for them where I live. I now feel confident recommending many newer non studded winter tires for all but the most severe conditions. When you get to that point you will need a 4 wd.
For you, change now…and don’t drive any more than necessary of at speeds greater than 45 mph to a more trustworthy tire shop…
Shops in this area would refuse to outfit your car that way because of the liability.