Good post overall, but always try to seek out the latest information on any given matter. Technologies, manufacturing processes, etc. change over time.
I noticed that the dates on the oil spec documents appear to be 2013. So there may be numerous new lubricants that meet or exceed the specs that...
My third cousin's brother in law's two doors down neighbor works at a tire shop, and they use this for folks who ask about the yellow and red dots.
https://www.amazon.com/Black-Paint-Pens-Permanent-Markers/dp/B0C58HX1JV/
If you haven't replaced the main battery that could be the issue, especially after it spent much of its life trying to recharge the Aux battery while that was still connected in parallel to it.
I'd get a good test on the main battery and go from there.
Everyone who owns a Jeep should learn how to run the steering through a DIY inspection process at least once every six moths. More if you really wheel the thing.
Lifts, bigger tires, higher offsets, and even missed torquing from the factory can all lead to steering and handling issues pretty...