I spent some time in the car while it was plugged in (Level 2) and the A/C (whole car) on, just reading the owner’s manual. It seemed that the A/C was drawing more current than the Level 2 cord could supply and the battery was going down while plugged in. How much power does the A/C need and is the 120V convenience cord supply enough to match the A/C need?
With Level 2, car can draw about 6.6kw from wall but then about 800watts are used for accessory. Now with full AC on, you may draw more than 5800watt and so your high voltage batt may drop but this should be a very slow and small drop.
With level 1, car can draw 1.4kw but with 400watts for accessory, you only have 1000watt Vs more than 5800watt draws with max AC. So you will deplete high voltage faster.
While in pre-conditioning (how you set up you go time and temp for car to condition for your trip), these draws are managed smartly and so high voltage battery drop in that scenario is less.