I think you are correct, in separating the functions of AC and DC in most efficient way.
How to power the Air Conditioner when away from a campground with 30a pedestal is the killer app...and you have enough reserve in that Anker...the question is how long?
That depends on variables like how hot is ambient air? how cool are you running the AC? how long?
Like the fridge...
if I am freezing water bottles overnight in my Dometic in the Sonoran desert at 85 degrees low humidity, its not as efficient as say, Floriduh at same temp 100% humidity...
Resistance in lines and connections also gobbles up power- so a long skinny AC extension cord uses more than a short fat one.
You might consider power out from the Anker to fridge via another DC outlet. Cigarette plugs are popular but also notoriously inefficient.
Does it have Anderson outputs like Goal Zero or other DC outputs you can make a pigtail to convert to match what plugs into fridge?
Changing CPAP to DC, yep. Dont use the humidifier heat function if possible...
Powering the Air Conditioner directly vs going thru the CI wiring - yep.
That would avoid the Anker topping off the CI battery, and converting to DC for the rest, and powering all that wiring- more resistance.
Let the house battery run everything on DC, and see how long it does. Fan draws some power, CPAP...maybe recharge phones and laptops in car off the Anker, along with fridge?
So, then trick will be how to power the AC alone...
If you can pull the AirConditioner you can see how its wired- again thats a Craig question, but if you can access that and splice in alternative AC plug and isolate rest of system...hmmm.
Like some of us who are adding new stuff in ways not available back in the day, its owner DIY of course...not factory warranty help, so at some point I figure I have to learn and DIY...a useful challenge and skill for other repairs down the road...maybe
maybe
@Sweeney could be persuaded to accept a zoom consult for $$$. Or refer you to one of the RV Geek networks of folks like him...
It gets tricky and I say this as someone slowly puzzling thru things that are inherently obvious to people who do it all day, but ya gotta get your multimeter and ammeter in hand and patiently follow the logic chart.
"Where does the elbow bone connect to the shoulder bone to the..." and RTFM is my favorite reminder from car forums for noobs like me...
PS: Does the Renogy panel have an integral solar controller? Bypass or remove that as thats what Ctek does once solar connected.
As far as the Ctek-Renogy voltage shutoff- I'd call Ctek and Renogy or search for someone in a forum thats asked that. Amazing what AI like Grok can turn up, inc youtubes.
PS2: the plug connected to battery- did you call
@Lipster ? That looks useful but lightweight like the signal wire on CTEK, that tells it your house battery is flooded lead, AGM, or lithium. Have you double checked that is correct for the battery you have, if you have replaced the CI house battery?