Welcome to the DashCamTalk Forum,
Great to read your comments and questions, they help so many others reading these messages.
Any Dashcam powered internally with lithium batteries while mounted on windshield in full summer sun will always fail due to high heat, very bad design.
You have asked and identified the most important reason NOT to use a Dashcam Hardwire Kit with Parking Mode = Winter ! Allowing any accessory to drain vehicle battery voltage under 11.7volts when winter temperatures are below -15C in my opinion is crazy. My old 4x4 Truck always started at -30C without block heater in parking lot for 8 hours, but anytime Dashcam Parking Mode was enabled with "any" Hardwire kit for 8 hours Truck almost didn't have battery power to start, failed few times.
Hardwire Kits are perfect when used with newer batteries (not 5years old) for 18hours or less in temperatures +30C to -5C, beyond those ranges expect issues.
Power Banks are a great alternate Dashcam power source for Parking Mode Protection _if_ Power Bank is high quality and reliable. There are dozens of 5volt Power Bank brands and models to choose from, always read reviews for known issues. One reason I selected VIOFO Dashcams was they use standard 5 volt power. Buy a 5 volt Power Bank from established company, ensure PB has minimum 1 year warranty, select 10,000mAh for 6hour runtime or 20-30,000mAh capacity for extended Parking Mode coverage. Downside to Power Banks is they take 4-6 hours to recharge and the thinner ones don't work well below -5C. I don't recommend charging the Power Bank in vehicle while it powers Dashcam due to excess heat created in lithium cell - unless the PB was designed for that functionality.
My Daily Driver Setup = A119S+MOD-4Vf ((A119+5Rf)) powered by socket adapter then switched to Power Bank for short duration Parking Mode. Here in Vancouver Canada it rarely drops below -10C in winter so Hardwire Kits are acceptable but my compact car battery is tiny with insufficient reserve power.