Which rating current are you using currently?
Anker or RAV power.
Rest specs and price vary, check rating that supports fast charging for both ports.
5V 1.0-1.2A - Normal charging (slower).
5V 2.4A - Fast charging.
QC 2.0 - super fast charging.
QC 3.0 - lightning fast charging.
They are backward compatible, so the higher rating, the better.
For car charging, aim for atleast 24W dual port car charger, which will be 5V 2.4A on both ports. Too much fast charging will heat up the phone in summers and may cause safety risk. Anker Power Drive 2 is 24W 5V 2.4V (Fast charging) on both ports.
If old car, test battery and voltage of cigarette lighter and add relay if voltage is lower even with new/healthy battery. This is very important for old cars.