I understand your reservations about UPenn, but I’m not sure UChicago is any less worthy of reservations ( The Plight of Transfer Students – Chicago Maroon ), and you have a much more solid rationale for why Penn works for you academically.
Based on everything you’ve said, I’d go with Penn, and start strategizing about where and how to meet likeminded people. Probably the kind of classes you’ll be taking will be a good social incubator, for starters, but also consider what extracurriculars might help you find your tribe. There are undoubtedly other tribes - even larger ones - who aren’t “your people,” but that doesn’t matter as long as you find the peer group you’re looking for.