XT30 will carry 30A continuous, I can’t imagine the charger you’d need to exceed the capacity of an XT30.
Also there is no such thing as XT90S male. All male are XT90. XT90S female are the antispark connectors with the green stripe.
Male have pins, female have holes.
12AWG wire is way too huge for a charging circuit, it just wastes weight and cost, try looking at the table. 16AWG - 18AWG is probably plenty. Going too big on wire past your current needs can be bad because during catastrophic failures, it doesn’t fuse away as easily. Likewise, for very low currents, in the sub 5A range, going too small can be bad because the tiny wire sizes don’t handle prolonged vibration as well and can break near or at joints.