Perhaps the rate they show isn’t accurate then.
The schools listed OOS make your budget - either at full cost (Purdue) or with merit aid. Again, if you think you’re in at UIUC, then fine but it’d be criminal to not have a back up.
You still need to do a net price calculator to see what your costs would be. Some will have income tables (assuming average assets) - for example, at Stanford, your full cost would be covered. See the link below.
I would have schools other than UIUC and your others. You had UIC and IIT (if you can afford it)…so if you are ok with those as safeties and willing to attend one, then you are ok.
Direct from the UIUC website:
Admit Rates, Undergraduate Admissions, University of Illinois Urbana-Champaign
Stanford expands financial aid for 2023-24 - Stanford Report