Any way to trick the traction battery heater into running after 3 days?

Now that I'm not driving to work everyday, it's likely my Prime will sit in the driveway or my detached unheated garage some days this winter. For cars sold outside of Alaska and Canada, the traction battery heater only runs for up to 3 days. Is there any way to trick it into running longer? For example can I put a mechanical timer on the EVSE that "unplugs" it for a few minutes each day? Or do I need to go outside and physically unplug the connector from the car and plug it back in? Or do I need to use enough energy from the battery that the car charges again?

This weekend is a good example. I plugged the car in on Friday afternoon. 3 days later is Monday afternoon. A snowstorm moved in, so I'm not planning on driving anywhere before Tuesday if I can avoid it. But Monday night (after the traction battery heater stops) is supposed to get down to 6 degrees F! I'd like to have a warm battery if I drive anywhere on Tuesday.

 

• As the battery gets colder the EV mode range decreases. It's already not great at the temperature the battery heater keeps it at (around 32-36F).
• As the battery temperature drops, the power output in EV mode is limited. Sometimes that causes the car to suddenly turn on the engine. Depending on the driving conditions, it might also bypass the warm up cycle if power is needed immediately (accelerating or going uphill on the highway).
• Charging a lithium battery when the electrolyte is frozen can permanently damage it. Regen braking also counts as charging. The car should protect itself, but from what I've observed in cold weather with the hybrid Assistant app, I'm not sure I trust the car to sufficiently limit regen when the battery is cold. On one drive home from a ski trip, the battery was at around 28F. I think I saw 20kW into the battery a few times before it limited the charging power to about 1-2 kW for most of the next hour.
• If the car does limit regen when the battery is cold, that greatly decreases efficiency.

Its going to be something like 40 degrees on Tuesday, so I'd like to drive in EV mode. I most likely won't go to work on Tuesday either, so if I go anywhere it will be a short drive, hardly enough to really warm up the engine. The battery has so much mass that it could easily still be below freezing for a few hours after the temperature outside reaches 40F.

And, I'm sure this is just the first time this will happen this winter. Last year I had no problems because daily driving and charging kept the battery warm, and the traction battery heater kept it warm on the weekends.

 

I did use Google, but I couldn't find much definitive information. Most sources say the problem is charging below 0 degrees C, regardless of the temperature the electrolyte freezes solid.

For example here's a paper talking about a new technology to mitigate the problem (but it came out in 2018, so Toyota probably isn't using this technology. The background information is helpful. Fast charging of lithium-ion batteries at all temperatures | PNAS

As much as Toyota tries to make cars that are appliances that don't need any thought to drive, they are not perfect and it's still possible to cause accelerated wear or damage to your car in some situations. Maybe they have it figured out, but why risk it.

Regardless of possible degradation to the battery, I'd like to use the car as an EV as much as possible. It is very hard to stay in EV mode when the battery temperature is below 0 degrees C. The battery heater is only around 100W, and it only runs enough to keep the battery between about 32-36 F, so that certainly uses less energy than using the ICE.

Finally, if it doesn't matter, why do they have a different battery heater control for Alaska and Canada?