Jaded, bored, sarcastic OLD forum members here. Pay them no mind. The "old" part is okay.
I use distilled water in a spray bottle as my first step. Spray a cleaning rag to moisten it, then start rubbing. I'll use elbow grease before I go to anything like a chemical. Isopropyl alcohol is next: it will take down almost anything that water will not remove. (The exterior I treat the same way.) So far, I haven't required anything else. Always start with distilled water before you graduate to something stronger.
Quick wax on interior. Clean leather and steering wheel with a new magic eraser each time. Finish is satin new , no scrubbing, just drag it along wet and dab up the excess water. It pick ups a ton on dirt and grease.
I used this combo of Chemical Guys products on the leather in my previous car and it left the leather looking, feeling, and smelling great. Smell is like a light new car smell; nothing remotely offensive or strong (in my opinion). Only had the Stinger 1 week so haven't had cause to use it yet but am excited to.