If you tell me what your project is then I'll do it in DEX and you can do it in your program and we can compare. Sounds great to me. I'm sure everybody will look to compare the results.
P.S. Please bear in mind I'm not a professional PCB designer.
It's a spare time project and far from a finished PCB, but if you want to have a shot, we can simplify it to the basics.
Do a 7 port USB hub, self powered, with a high frequency switching power supply from 19V input for power (~4A @ 5V, also almost certainly a 3.3V rail at ~0.5A for the hub). Standards compliant and correct differential and single ended impedance (that'll mean 4 layers, typically.. other requirements in my project push me to that anyway). Something likely to pass USB certification.
This'll get you doing QFNs, high frequency power, controlled impedance, and dense layout.. And no, before someone calls me out on it, there's no dual row QFN involved in this, that was just an example of a slightly more complex footprint.
Bearing in mind you're not a professional PCB designer (nor am I, mind you), this may be quite a steep order. However, it's the sort of thing you need to show if you want to sell your program to people doing such layouts, for work or hobby. This is the sort of project free_electron was going to be making as a demonstration piece for you.