I’m looking for recommended developers company to develop a system to control large amount of rotors, each rotor with its own ESC using mission plan.
Why not do it yourself? it is documented: Copter Motors Library — Dev documentation in C++
or in LUA(does not even need to recompile the code, nor upload firmware) : https://github.com/ArduPilot/ardupilot/pull/15708
Here is a LUA example for an hexacopter: https://github.com/ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/examples/MotorMatrix_fault_tolerant_hex.lua
It is easily expandable to up-to 16 rotors.