Brehs I'm getting into the documentary game....got a 4k DSLR camera and I was looking to buy a work station but I'm hearing you can build a good one at less than half the price..is this true??

I need a work station that can handle high quality video editing with serious speed, highly efficient processor, 4k resolution input/output (video cards etc...) , ram specs, motherboard, speakers, body/frame, card slots, Ethernet ports, WiFi cards, and whatever else is needed for complete machine...I know its a lot so I will take whatever help I get brehs...