I genuinely appreciate all the help! Thank you very much.
A few things for clarification:
I generally only use the multicooker (Instant Pot Mini) while driving home from my commute (20 minutes). The cooker usually is only on for about 20 minutes. It's on pressure cooker mode, so it doesn't use full power except in the beginning and then sometimes in the middle to keep the pressure up.
(I am cooking 12 ounces of raw beef for my dinner)
Cooking with propane or using a generator doesn't feel very feasible for me at this point due to various factors (space, no stable place to park my van, etc.), although I will continue to consider all options.
I am feeling like I'm going to upgrade the alternator, add a deep cycle house battery, and get a new inverter. I will continue to research / re-read your feedback and feel it / think it out.
Again, much thanks for all the help.
L