For self hosted / cohosting my own kit, I buy refurbed servers from https://www.etb-tech.com/ because I can spec exactly what I want and see how the cost varies, what the delivery time is, etc.

Years ago Broadberry has a similar thing with Supermicro, but not any more. You have to talk to a sales person about how they can rip you off. Then they don't give you what you specced anyway -- I spec 8x8G sticks of ram, they provide 2x32G etc.