If you were to split the battery into two parallel units, you could hypothetically charge at twice the current. TL

R; you're going the wrong way.
As KiwiME points out, the battery itself sets the amps. The general rule is battery charge/discharge rates are based on the battery capacity. A rate of "1C" means you are charging/discharging at a rate that will fully charge/deplete the cell in 1 hour. So a 60 amp-hour cell would have a "C" rating of 60 amps.
Cells connected in series must have the same current, so two 6o-amp-hour cells in series would still have a "C" rating of 60 amps. However the voltage would be double, so you'd get double the
power. (Power = Voltage x Current)
Charging two cells in parallel would allow for 120 amps, because each of the two 60-amp-hour cells is charging at 60 amps. However this doubling of current comes at the cost of half the voltage, so you still get double the power.
So there's no actual advantage to splitting the battery like this...
unless your power supply is limited either by current or voltage. Most (all?) DCFCs are limited by current, e.g. CCS spec maxes out at 350 amps, but can (and must) vary the voltage over a wide range. This is why we're starting to see vehicles with 800-volt class packs (The Kona's is 356 volts nominal, putting it into the 400-volt class). Twice the voltage means twice the power without increasing amps, and that's good because amps is what causes losses and heating. Instead of splitting the pack into two parallel sub-packs, you want to reconfigure it into longer series strings for higher voltage.
FYI this is exactly what Hummer EV's pack does; Two 400-volt packs get internally rewired into a single 800-volt pack for faster charging. An ideal 800 volts at 350 amps is 280KW, and the Hummer is said to charge at a peak of 250KW.
I guess you could say less is more?