It’s as simple as that
“Motor Current Max Brake” is for total brake strength and especially for mid and slow speed
“Battery Current Max Regen” is for brake power at high speed.
But in your case -5A for “Battery Current Max Regen” will limit the brake power at nearly all speeds because it is too low.
If you Battetry can officially handle 2C charge current (5Ah * 2 time capacity = 10A) you can set it to 10A. But even that is a bit low. I recommend to go even 50% higher than that because to my experience these max charge current ratings are only for continuous charge and not for short bursts which take mostly not longer than 5 seconds.
So even 15A shouldn’t harm your battery.
And when you think about it, your APS 120a RC ESC didn’t give a fuck about any max charge currents specs.