Lithium shipping charge standards has been 50% for a good while. The problem has been stock that is SO old even that has slowly discharged. Higher charge provides more power for potential fire threats.
I have a Nissan Leaf electric. I tend to keep the charge down at 30-40% when not being used.
Look at some of HJK battery/charger postings. Test/Review of Samsung INR18650-35E 3500mAh (Pink)
At some point the charge will start to decrease working toward termination. That’s the ramping down. Discharging amps should not have any ramping (voltage does drop). It goes where it is set until it hits the cut-off, then just stops.
Manufacturers give specs on charging and discharging rates. (See specs on link above). For 18650 I personally tend to use 0.5A if I’m in no hurry. 1.0A is not a problem. 2.0A is acceptable if in a hurry and it’s a quality battery. You can go higher, but that’s pushing it a bit. Larger batteries can be charged at higher rates. Small batteries, older batteries, lower rates.
The higher the charge rate, the more heating it may have. Higher resistance adds to the heating problem. Heat is not good for any battery. Higher rates detract a bit from longevity.