According to what I’ve read so far, I’m getting a bit confused to be honest 
. I’m considering to buy this powerbank and I believe it should be enough RAVPower 20100mAh Powerbank USB C Power Delivery: Amazon.de: Elektronik .
Also this one is a nice upgrade for 10EUR more www.amazon.de/-/en/RAVPower-Power-USB-C-Delivery-Black/dp/B0831G4F38 .