Question about Corsair RM750x *2018*

The PC should work like this, the power supply is guaranteed to deliver enough power and all parts seem to fit.
But if you don't need the PC urgently, here's a tip: I wouldn't buy the parts now. Next month (15 October if I'm not mistaken) the RTX 3070 graphics cards will be released, which should sell for about the same price as the 2070 Super, but will be quite a bit faster. And even if you don't get one of the 3070s, the price of some 2070Super models will definitely come down, as is currently the case with the 2080Super and 2080Ti. And as far as the processor is concerned, the new processors from AMD will soon be introduced, so you will certainly get more performance for your money in a few weeks.

No, unfortunately you still need a few parts. You still need to match the socket of the mainboard and the processor, and water cooling wouldn't be a bad idea either. (I'm no expert either)