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 several 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.
You are not good as electrician, safety it’s first place for electrician all time and no big difference of 10kW and 100kW, license is not for 10kW or 100kW of power. You can receive license for system up to 1kV(most popular) or for up to 10kV+, but it’s not a kW!