Hi,
I am a CC lurker and felt compelled to create an account to respond to this, since I was in a similar position as you last year (currently gap yearing) and was seriously torn, and didn’t have a ton of useful feedback because people thought I was crazy for thinking about turning down Princeton (I was deciding between Princeton, Penn, and UW). I ended up going in state over the other two, in part due to money but also due to premed concerns. I am not FGLI so that wasn’t a huge factor in my decision, but I was concerned about both the premed experience and the general fit of the university (how cutthroat a college is, student life, etc).
You’re right that Penn pre-med is notorious. 2 of my older friends from HS are Penn pre-meds - when it was down to Penn v UW (I decided against Princeton first because (1) they don’t have a med school and thus less opportunities for research (2) notorious grade deflation (3) I wanted to live somewhere more urban. They talk about how they’ve gotten rid of grade deflation but its kinda hard to “get rid” of something that has been part of their culture for so long), listening to their experience helped me rule it out. One was valedictorian and the other was also at the top of her class (and both people I consider much smarter than me tbh), so seeing them really struggle and cry over grades was really sobering for me. I think it’s important to recognize that yes, premed is tough wherever you go, but you’re often being compared to other students in your class, and competition will be a lot stiffer at Penn. There are only so many As that professors will give out. This shouldn’t scare you from attending a college, but I think it’s something you should definitely be aware of: your goal is to become a doctor, not just to be a college graduate. They (and a lot of my other friends in college) have told me stories of so many premeds dropping out because they couldn’t handle the courseload/competition and their GPAs literally weren’t high enough to even apply.
Beyond the pre-med scene, Penn sorta has a bit of a reputation for being cutthroat and hyper-competitive (especially because of Wharton kids). Again, I’m not a FGLI so please take this with a grain of salt, but I have heard from friends about the lack of support for FGLI students despite the admin really advertising how FGLI friendly they are. You want to enjoy your college experience out of the classroom, too. I thought that the chiller and more collaborative nature of UW would fit me better as well. Penn’s lack of school spirit also deterred me. Obviously, this is personal preference. But mental health is important both in and out of the classroom, so I would take the general experience into serious consideration.
My friends at different colleges generally seem to enjoy college life, but when I mention premed, they’ve always told me it’s better to be at the top of your class at a very good school versus middle of the pack at a hyper elite school. GPA and MCAT matters more than undergrad name, and life isn’t just about the college you go to. I’ve heard undergrad name does not matter that much, so choose the one that you can do better at. If you were interested in i-banking or something I would recommend Penn. If you aren’t sure or wishy-washy about wanting to be a doctor, then Penn could be a better safety net than UNC in terms of employment. But if your backup choice after med school would be research or Phd or something, then grades still matter a ton, and I would choose the school that would allow you to stand out more. If you are fairly sure that you want to be a doctor, I feel like UNC would be a good choice for you, since it seems like my UW versus Penn dilemma was similar to yours. Tbh UNC is a better school than UW with lots of premed resources, so I feel like my choice would be UNC in your case if you are seriously concerned about maintaining GPA. In terms of internships and resources like research, I realized less competition could be a good thing. Again, it’s all about GPA, MCAT, and standing out for med school.
I’ve heard advice that if you know you’ll be going to med school or graduate school, it’s a good move not to pay too much for college. Not sure what the cost difference between Penn and UNC is for you - if it’s only a couple thousand dollars, then idk if it should be a big factor in your choice. If you’re comparing $5000 versus $25000 a year, then I think the cheaper option would be a no brainer.
Anyways, I hope this was helpful!! Sorry it was such a long message, but it reminded me a lot of my situation last year when I wished someone would take my situation seriously. In the end, I basically decided that any regret I would have choosing a lesser ranked school would be nothing compared to the potential regret of not being able to follow through on my lifelong dream of becoming a doctor because of some temporary prestige chasing. Both are amazing schools and I’m sure you’ll be happy with your choice either way 
Feel free to message me and good luck!