Questions about Corsair iCUE 4000X RGB Mid-Tower White tempered glass case

just the three fans in the front are included

I don't have any experience, but it won't be much different from other cases, the graphics card gets hotter in the vertical mount, it doesn't make any difference whether it's glass or metal. I recommend the normal horizontal mount, even if vertical looks cooler ;-) I would also mount the NZXT on top of the case because of the water bubbles that form over time. JayzTwoCents has a great video on this. But of course I don't know your setup.

Cable incorrectly connected

Hi you. Even though it's "budget", I wouldn't skimp on two things: SSD and CPU cooler. For the CPU cooler, I recommend Corsair iCUE H100i Elite Capellix (27.70 cm). As SSD e.g. Samsung 980 Pro (1000 GB, M.2) Also missing is 1 case fan in the back, depending on the graphics card it could get quite warm. And either 2-3 fans on top or even better an AIO. As heat conductive paste I recommend Grizzly. The rest should fit. This is for example my PC (+ RTX3070), runs like clockwork :) https://www.digitec.ch/de/shopList/show/f348669a1289169b39b3eaa646189410

There is no such thing on digitec, I don't think.

https://www.corsair.com/de/de/Kategorien/Produkte/L%C3%BCfter/RGB--und-LED-L%C3%BCfter/iCUE-SP-Series-RGB-PRO-Performance/p/CO-9050094-WW

Unfortunately, we do not have any information on this at the moment. Should the product become available to us through our suppliers, we can check a possible inclusion.