The big problems with case fans is they encourage dirt and dust. It's just a reality that all bodies, human and otherwise, shed loads of skin. Add to that any other airborne particles.
The ideal would be large extract fans, drawing air out with as little resistance as possible, plus filtered intakes. But the filters would themselves, need to be designed with limited air resistance and ease of access.
I'm in the process of building a new PC. I've been looking at loads of different cases. Filters top and bottom even on sides. Yet frustratingly, many can only be accessed from the back!
The filters must be cleaned regularly. Removed, vacuumed then possibly washed and dryed.
Most seem to drag air in and let it bleed out wherever. Utterly pointless. The air intake has to be filtered and those filters will, by definition, limit flow.