Swap your "Novation Launchpad" and old phone for an "all-in-one" device.
The project is designed for the Novation Launchpad X and iPhone 8 Plus (but you can customize it for your own phone).
You can create your own version of the Akai MPC / Novation Push / Native Instruments Maschine+ for less than a quarter of the price.

Thanks to the large built-in battery, you can create music anywhere without worrying about power. The enclosure keeps everything in one piece, eliminating tangled cables.

The project is designed to fit the following inside:

A power bank (in my case, a Green Cell 10,000mAh)
A USB hub to connect the phone and Launchpad together
All necessary USB cables
Optionally, an additional sound card to split the signal into "input" and "output"
If you have any questions, don't hesitate to contact me.