Umm, you need to do it on your own. Fact.
Or you can buy a PC for $3000 that will own, prebuilt.
Many makers out there, you figure it out.
Or, I can build it. 5 hours of build homework, $250 total, many PMs emails and work arounds with the buyer.
Build the PC, $300.
Warrenty it, $500.
Want watercooling? $50 per hour to build, minimum 12 hours, add 8 hours at $15 per hour to leak test.
Watercooling watternty IF you pick it up? $700.
FACT.