Samsung power bank are great and should keep it.

All other brand stated fast charge with 5V are Bullshits.

9V 2AMP 18W is the key to fast charge. and with Good DC-DC buck boost converter / controller that with high efficiency and low harmonic distortion ONLY SAMSUNG DID IT.
SAFE, POWERFUL, QUALITY COMES WITH PRICE.

FYI, Cheap charger or powerbank can damage your phone. such as touch sensor, and motherboard damage.

Good luck.
Thumbs up for the price. That's very cheap. I have a units as well from S8+.