Recommended High end & solid Pc or mac & GPU for heavy duty encoding.

Hello,

I have a huge video library of almost 500TB to transcode from/to multi-video formats 4K and FHD, for example :(MPEG-4,MPEG, DivX, MXF)

Which path to go nowadays, Mac or PC, server or workstation, to use adobe media encoder at its best and maximize the transcoding speed.

also what the best GPU ATM for that task?