It sounds like you need a Thunderbolt dock, not a USB hub. Maybe one like this: https://eshop.macsales.com/item/OWC/TB3PRODCK/
The reason I suggest a Thunderbolt dock is because I have yet to see a USB hub or dock that provides more than 15 watts to a downstream data port. I assume you are using a Lightning to USB-A cable to plug in the iPad, that's going to limit power to the iPad to 12 watts, maybe 15 watts. Even if you are using a USB-C cable I have yet to see a USB hub with a charge and data port that provides more than 15 watts. I suspect that the iPad is charging fine, it's just that by streaming music constantly it is consuming more than the 12 watts provided.
You'll need a quality Lightning to USB-C cable to get more than 12 watts into the iPad. I emphasize "quality cable" because I bought a non-Apple brand Lightning to USB-C cable only to find that it did not support USB-PD and therefore was limited to 12 watts to my iPhone. Apple's USB-C cables will pass more power, as I assume would a better built cable from someone else. I suspect your iPad came with a Lightning to USB-C cable, use that. I will assume and suspect a lot here, you didn't specify everything I need to know in your question.
Even if your MacBook Pro doesn't have Thunderbolt/USB-C ports you can still use a Thunderbolt 3 (USB-C) dock on a Thunderbolt 1 or 2 (mini-DP) port. A Thunderbolt/Mini-DP to Thunderbolt/USB-C adapter will allow you to plug in the dock and still get the full Thunderbolt and USB 3.x bandwidth. The reason you want the Thunderbolt dock is to get a more powerful USB-C port (as in more than 15 watts), and is still full bandwidth, for your iPad and all other devices.
Assuming you get a Thunderbolt dock like that I linked to above you will find two Thunderbolt/USB-C ports, one of which will be labeled for connecting to the laptop. Don't connect the MacBook Pro to the laptop port, that's for the iPad. The goal is to get most power to the iPad, and that will be on the port labeled to the computer. Connect the MacBook Pro to the low power Thunderbolt/USB-C port, leaving the laptop to run from it's bigger battery or from a power brick plugged in directly. Thunderbolt is not like USB, Thunderbolt is peer to peer and so "upstream" and "downstream" lose some of it's meaning, connecting the Macbook to either Thunderbolt port will give full function and bandwidth.
Now my disclaimer. I have not tried this myself. I'm taking educated guesses based on my experience with Apple hardware. There may be a cheaper non-Thunderbolt hub or dock that can provide both power and data, I simply have not seen one in my own searching for my own needs.