It sounds a bit like you are trying to find the perfect place for you, but I’m here to tell you that it doesn’t exist.
There will be things that you don’t like about any college you attend. Every other college will also have attractive aspects to it that you wish you could experience. The key to really enjoying your experience is maximizing the things that you love while minimizing the things you don’t enjoy or don’t care about. There’s no such thing as THE right place for everyone; most college students could and would thrive at a variety of places with the right mindset.
You’re closer to home, which means you can visit more often and be less homesick. You’re in a vibrant city with lots to do and explore, and opportunities to intern or work part-time during the academic year. Ignore other people’s responses - who cares what they think? People know Big 10 schools because of football; they often don’t appreciate smaller, less well-known schools, but that doesn’t mean your choice was bad. You have a bit of a nostalgia effect, and also you’re remembering the things that were good about UIUC - because there’s good in every experience.
You do seem to want perfection and you also seem to want it right now, as opposed to giving it some time and let things develop. But if you transfer back after your sophomore year, that’s when you start to lose some time and face the chance of having to take 5 or more years to finish college. That’s not a catastrophe, but it does get expensive and should be avoided if you don’t have to do it.