One marginal "free with purchase" cheapo battery with likely a marginal converter charging it has no chance of running a fridge even on LP for 24 hours.
I'm in a similar boat, except I understand why my system is marginal and I have good batteries (plural). Cheap converter doesn't charge properly.
Except I use the camper very rarely and have onboard genny at my disposal. If I had the time to repair and/or the need for a more competent system, my WFCO converter would already be in the landfill and a PD converter would be in it's place!