just google the quickcharge specifications...(got it all from wiki) Quick Charge 3.0 is clearly stated here that the product supports it.

Quick Charge 3.0--> 3.6 V to 22 V --> in steps of 0.2 V also--> 2.6 A or 4.6 A resp.--> 18 W

Exciting info I have found:
Unsuitable for Quick Charge are the so-called fast charging cables. With these, the two data lines of the USB standard are short-circuited, but Quick Charge needs them for voltage sensing.

But the product still says the following: Output current 3 A, but there are two usb ports, so it must be at least 5.2 with two times 2.6?

With the 3A, I assume that this applies to both USBs when charging at the same time, which can no longer correspond to Quick Charge 3.0, or?

Thanks for the question, it helped me to recognise the problem and digitec should help to categorise all powerbanks better and to specify the specifications exactly if they want to.