BQ25570: What voltage / current input is optimal for the BQ25570 chip?

Part Number:BQ25570

I am trying to charge a supercap using solar panel with the BQ25570 chip.

I searched for solar panels and there seem to be various options outputting high voltage / low current, mid voltage / mid current, or low voltage / high current.

For example, KXOB22 series has options such as 630mV / 50mA, 1.5V / 15mA, and 3.4V / 3.8mA

I wonder if one is better than the other when paired with BQ25570, and if so, which and why.

I suppose those outputting too low voltages might be bad because BQ chip has 600mV cold start voltage (am I correct?)

It seems like when I look at the datasheet, higher voltage has higher efficiency, but the graph (Charger Efficiency vs Input Voltage) is for the same current.

Now that I have varying current, I am not sure if higher voltage with less current will be more efficient or it would be the other way around.

Thank you!