You don't need to 'run the heat pump'. It is running already, whenever required, even if you're not around. And, because it is running, your batteries will not

You don't need to 'run the heat pump'. It is running already, whenever required, even if you're not around. And, because it is running, your batteries will not reach a temperature where they start degrading. And, yes, this means your driving range is reduced slightly, but because heat pumps are so efficient, and because the alternative is, as you so eloquently observe, "car is dead", it's... sort-of worth it? And the wonderful thing is: this works in both extreme cold and extreme heat, because heat pumps are reversible! So, for a little bit of battery power/range reduction (let's call it 20%?), you keep your EV (and the planet!) alive a little while longer. Now, I don't have any experience with 'the Yukon', but I can tell you from personal experience that: a Volkswagen Transporter, used for staff and goods movement in Greenland (so, short distances only: all serious travel is done by plane or boat), that in its fossil-powered incarnation would need to run 24/7 on diesel for a good 90 days a year, works perfectly fine year-round in its heat-pump-upgraded EV life.