Honest Q you’ll need to answer….how would CORE help you improve this? All the steps you can do to moderate body temp you (I assume) already know….so you should be employing those tactics when the temps are high and you suffer. Knowing your exact body temp doesn’t change that.
I have a CORE and have rarely used it….I did use it pretty extensively for a couple of weeks last summer as I prepped for SBT GRVL and I did some specific heat adaptation training, but other than that, it has been more of a curiosity more than anything else.