Draining RV battery

Hello everyone, I hope your all doing well. New to RVing and recently purchased a class A 1994 Ford Fleetwood Southwind. I'm full-time in the RV.

The RV was disconnected from shore power about a week ago. I don't drive it very much and it's often sitting parked for 12+ hours a day. I went to start it last night and engine would not start. I learned by accident what an Auxiliary Start button is for (thank God ??) and was able to start the RV.

The fridge runs AC & propane. Mostly using propane. I usually run generator each day to charge outlets (power laptop). Besides water pump, I'm not usually using much electrical power at all.

I have a few questions about my batteries being drained/charged:

Is charging my cell via cigarette lighter draining too much battery?

Will this emergency auxiliary start button work every time I need it?

Is battery having problems due to being parked all day?

If I turn off the LP Gas Detector to save some battery, will this cause the propane for fridge to stop working?

I've searched online and have not found answers to these questions. Any help/guidance you can provide is greatly appreciated.

Kind regards,
Robin