Here in Davis, California we frequently have temps over 100. And in my non-insulated garage it can be 110. We had two Nissan LEAFs, which lack thermal management, and both showed substantial loss of range after two years, and by the end of their three-year leases they were almost useless. Thank goodness we leased so we weren't stuck with them! We've now had two Spark EVs, which have thermal management, and neither has shown any loss of range in 30 months, in exactly the same temperature conditions. So, moral of the story is make sure any EV you choose has thermal management. Sitting outside in inventory shouldn't have any noticeable effect. By the way, some EVs claim to have thermal management, but it's just a fan. What you want is a system that circulates coolant using a pump and a radiator. Chevy Bolt , Spark and Volt have this, as do Teslas. I'm not sure what other EVs have it, but I'm sure that information is available on various EV forums or from Internet research.
If it's a used car you're considering, all else being equal, I'd choose one that came from a cooler climate. You could check the CarFax to see where it spent its time before moving to Scottsdale. Even if it's from a hot climate, if the mileage is low the likelihood of any serious degradation of the battery is low. And remember EVs do have a really long battery warranty, so you're covered. If it's a Spark EV you're considering, remember they were only sold new in California, Oregon and (I think) Maryland, so the chances of its coming from a really hot climate are reduced.