I ended up just buying some generic ones at Costco. They work well enough and only cost me $20 on sale. I think the main reason that the vehicle specific ones all say not for the EV is because it might interfere with the heating/cooling. I only have heated cloth and it's too hot for me, so I wouldn't worry about it reducing the heat transfer. I was going to order some, but decided I'm just too cheap.
If you are interested in spending the money for vehicle specific covers then I would call them and ask some questions to see if you can find out why they specify them as not for EV.