Input on DIY budget cnc machine

[Noppishen]

I am in the planning stage of building a machine on a student budget.
Before starting building I'd like some input from people more experienced than me, this will be my first machine.

Build area is approximately 200*400*225mm.
I'd want it to be as capable as possible, but I will mostly cut aluminium or softer materials.

The machine would probably be made of mostly 20mm aluminium, it would be really difficult for me to work on steel, I also do not have the ability to weld.

I am planning to use a 2.2kw china spindle and HGR20 linear rails, used name brand ones, or generic new ones.

Motors would be 3nm Nema 23 stepper motors driving ball screws.

Id like to keep as many doors open as possible, I won't use flood cooling to start, but would want the ability to add it later. Will start with mist cooling.

The rails would be covered by bellows, they aren't modeled in the CAD.

The stepper motor mounts are not modeled yet either.

To increase the mass of the machine the steel beams that make the main chassis could be filled with concrete or something else.

Any input is greatly appreciated!