The moment the 12V system voltage drops under the approx 14.6 V that can only mean the LDC is in current-limiting mode, not a good part of the envelope to work in if you want any margin on your AC side.
Speaking of current-limiting, it feels like a good idea to hard-limit the current pulled from the Kona. If I use a second "house" battery as a downstream buffer for that purpose, is there such thing as a 12v DC-DC charger that can supply that house battery with upwards of 100a from the car battery? I could only find a 60a unit https://www.renogy.com/12v-60a-dc-to-dc-battery-charger/
Or combo an inverter+AC-DC charger to the car and feed the house battery that way? Plenty of those do 100a+, but bummer to need this seemingly extra power conversion in the workflow.
Or parallel a second battery with the car battery to minimize total voltage drop and thereby minimize current drawn from the Kona? I was reviewing the original power backup thread and saw this was @Fastnf idea from awhile back, if I understood it correctly.
Or just properly size an inverter (or an in-line breaker?) to trip based on load?
Ugh, wish I was in the electrical mystery and understood things more.