Audio Mixing Circuit Design

I'm looking for an experienced audio engineer or electronics designer to create a circuit for an studio headphone mixer. This circuit should be capable of handling 12audio inputs, primarily focusing on mixing various audio signals to a left right signal that sounds great. All Analog 12 input headphone mixing box. 8 mono channels with volume left / right pan controls, 2 stereo channels with volume only, and hard panned left right. Very good sounding, left right balanced outputs, 2 very good sound independent headphone amps with volume. runs on 16+,/16- bipolar powers supply. Has a multipin that that is buffered. if possible a simple tone control, Low , Mid, High frequencies on left / right mixer bus .

Also has a USB C connector to charge any rechargeable device from device

I want this to be similar to a Mytek Private Q system that is obsolete. It can power internally or with external PSU.

Key Responsibilities:
- Design an audio circuit that can be used for this in a 4x6 PCB board. Need to be able to solder inputs from a multipin to the board and solder thru to the board. Pan controls and volume need to connect to board easily, can be with ribbon cables or internal connectors
- Ensure the circuit is robust and versatile enough to handle abuse in a studio or live environment

Ideal Skills and Experience:
- Extensive experience with audio circuit design
- Deep understanding of audio mixing requirements
- Proven track record of designing circuits for handling diverse audio inputs.