All seasons are “not great” all the time. Go ahead and order a winter set of Gemini’s from Tesla’s store. Less than $3k and you’ve got yourself a second set of wheels and tires (so longer durations between buying new tires), better range, and FAR better winter ability.
The only time I think I would want an all season on the 21s is if I was unable to store them above 40F year round OR the roads were always dry in the winter but temperatures were below 40F.
The compound on the summer tires can be damaged under 40F which can make them unsafe to drive even when returned to normal weather.
You might make it through some cold weather without issue, but it CAN happen and that’s a hassle I wouldn’t want. If you have a well insulated garage then they’ll probably be above 40F in the winter (just by a few degrees), a basement you can put them in, or even a rented indoor storage facility (if you already use it for something, I wouldn’t pay for one just for the tires).