If I can do this, I will not ask about creation someone else. I don't has skills and resources for this.
More cool area, less temps, less fan speed, less noise.
One 240 rad can't cool last Intel/AMD CPU + two GPU with temps lower then 70-80 at full load (without any overclock). I test it in Ghost S1 and know it.
For me also important visual ascetics of case and build. Transparent sides, e.t.c.
You need a proper DDC/D5 pump res combo to drive two radiator, also think about the reduced float rate on setup to get less pump noise.
A bigger Pump Res combo, ideal airflow orientation and clearances, the case would need to be bigger, closer to 20L at least. At that point, better off with Micro-ATX or ATX. Micro-ATX and ATX mobo requires proportions to change to look good, so the design would have to change drastically in pursuit of form and function balance.
That’s not the scope of this project.