76 Key Velocity Sensitive MIDI Keyboard

Hello ,
I am new to Arduino.
I am planning to make a USB-MIDI Keyboard. I have a keybed with 72 velocity sensitive keys (Motherboard Damaged Korg i2 Keyboard). It also having
After touch
Four direction Joystick ('-x' and '+x' for pitch bend, '-y' for modulation and '+y' for other assignable controllers)
Sustain pedal (Damper switch)
Two assignable pedals (like Volume[CC7], Expression[CC8]...)
360 degree Data/Jog wheel (3 pin connection, step type controller)
Four additional slide controllers (mono slide potentiometers)
Kindly suggest me, which Arduino should buy? also please help me to make the program(Algorithm) for making A best MIDI Keyboard with above mentioned controller features.
Thanks in advance

Kindly suggest me, which Arduino should buy?

Arduino Micro.

also please help me to make the program(Algorithm) for making A best MIDI Keyboard with above mentioned controller features.

Algorithm is that each key requires two inputs and your code needs to time the interval between one input switch being broken and the other being made. Then scale that time measurement into the range of 0 to 127 and use it in the velocity parameter of the note on MIDI message. With so many input pins to monitor you will need port expanders to get enough pins to drive a Matrix of these inputs. As a matrix comes in powers of two then a 7 by 8 matrix will be required with a diode on each contact so you can press more than one key at once.

You might be gathering that this is not a simple task.

with above mentioned controller features.

They are trivial compaired with getting the keyboard interface right. Just a matter of wiring the pots to analogue inputs and any switches required to empty locations in the keyboard input matrix.