Power a 2021 11 inch iPad Pro with an external battery.

When I was testing using my 2021 11 inch M1 iPad pro with the Blackmagic camera app, I noticed that my current power bank could not keep the charge level up to the current draw of the iPad when it was recording ProRes 422 to the external SSD.

Now I am using a Belkin 4 port USB-C hub to connect an external mic and a Crucial X6 1TB SSD drive. The hub has a 100 watt PD power pass through port which can pass 85 watts and reserves 15 watts for the hub.

My current power bank has a 30 watt max on it's PD USB-C port and a capacity of 50,000 mAh. Is there a recommended power requirement to keep the iPad at an adequate power level?