It will be cheaper if you do it by yourself, it’s really easy and if you have some electrical questions, just ask.
Bullshit. You are not talking about adding a few low power outlets to a room or opening up and working on a moderately low power (compared to commercial/industrial capacity) household breaker panel.
The knowledge required to properly and above all - SAFELY - do the wiring for 10's to 100's of kW of power is vastly different. Even more to the point usually mining farms are a business that should carry insurance - that is not going to happen if it has not been wired by licensed professionals.