OK - thank you for adding more info.
You should choose WUSTL.
Why - you love Chicago’s reputation. Well then you should love WUSTL’s reputation. You love the campus (it’s gorgeous) and dorms and that it’s got a b school and engineering school although I’m not sure your major.
You’re unsure of its reputation - but you shouldn’t be - it’s a top college, along the lines of Vanderbilt, Rice, etc. and in some quarters Chicago.
All schools have parties - I wouldn’t worry about that - but yes, Chicago is known to be more studious - not sure if it’s true - that’ll be student dependent. And you never know who you’ll connect with socially.
But it’s clear based on your writings that WUSTL should be your choice.
Good luck.