What you said is technically correct but my advice is don't focus so much on max current. As the others mentioned the mAh is the battery capacity; almost identical to how much fuel is in the tank. C is kind of an indirect and fuzzy way of talking about the battery's internal resistance or IR. All batteries have IR. When you draw current out of a battery, you will lose voltage due to the IR. The voltage you lose is simply the current times the IR. So if you have a 10milliohm IR (0.01 ohms) and draw 100 amps, the output voltage will drop by 1 volt. The implication is that a higher C battery should have a lower IR which may or may not be actually true. If your charger has an IR feature, you can measure IR. You can't measure C. Batteries with lower IR will deliver more actual energy to your car because less is lost as heat inside the battery.
So the strategy for choosing batteries is more like this. Buy the highest capacity that fits in you car and that you are willing to pay for. You want at least a half decent C, like 40 or more. If a battery has a higher C than that and doesn't cost a lot more, then it is worth considering. A simple test is to feel your battery after a run. If it is hot, then you probably have a battery with too high and IR. You can see that a typical capacity and a decent C would suggest pretty high current that you may never actually draw. A 5000mAh battery at 50C is "technically" capable of 250 amps. You probably never draw that much so its not the right way to look at it.
These days I mostly buy GenTattu batteries because they are available and reasonable cost. Here are all their 2S 5000's for example
https://www.genstattu.com/lipo-batte...31&voltages=70
You can see that they are mostly 50 C with some rated at 100C for which you pay a little more. They probably have a lower IR but you'd have to buy one and test it or find a thread where someone has posted test results. If you drive a 50C battery and its is barely warm after a run, then a 100C battery probably won't make much difference for you.
I have been running their 6000's for longer run time.