TL;DR: Use a PD-rated bank. Be careful with phone bricks, i would suggest the Anker 737 Power Bank 24000mAh PD since it handles the X-H2S power draw safely.

Quickly typing this while my gear charges... honestly, be careful with those standard phone bricks. I learned the hard way at a shoot last year when my camera just shut down because the voltage dipped. For a wedding, you really cant afford that kind of stress. Heres what I would suggest to stay safe:

• Get a SmallRig VB99 Pro V-Mount Battery 99Wh. It is super compact for a V-mount and has a screen so you know exactly how much juice you have left. I use mine on a small rig plate and it lasts forever.
• If you are worried about the USB-C port getting worn out, a Neewer NP-W235 Dummy Battery USB-C is a lifesaver. It sits inside the battery door so the connection is more secure. Whatever you do, make sure the power source outputs at least 9V/3A. I tried a cheaper 5V bank once and the camera wouldnt even boot up. Also, only use high-quality cables... cheap ones are just asking for a short circuit.