Taipei or Seoul in January?

Hello! I am an undergraduate student from the US, and I will likely have the opportunity to spend 3 weeks in either of the aforementioned places in early-mid January. I've always wanted to visit South Korea and Taiwan, and the flights are around the same price from what I'm seeing. Hence, I'm having a bit of trouble deciding between the two. Would anyone familiar with these cities be able to point me in the right direction?

The first thing I'm considering is whether or not the weather would be excessively limiting in Seoul. I'm from the Philadelphia area (around 2 hours from NYC), so we do get pretty cold winters, but I'm not sure how South Korea compares. I don't mind the cold and some snow, but if the weather is consistently severe enough to substantially limit travel and activities, then I would probably opt for Taipei.

I spent 6 weeks studying in Japan in 2025 (and had an incredible time), so I am somewhat familiar with navigating larger Asian cities. Great public transport is always nice to have (although I'm well accustomed to lousy transport here in Philly, lol), but my main concern is the ease and cost of access to the city and surrounding areas. From Taipei, I would like to take a day trip to Jiufen, and from Seoul I'd be interested in visiting the DMZ.

Not sure how big of a factor this would be, but I'm on the Autism spectrum. I can travel and live independently, but I do find certain things such as sensory overload and social interaction more challenging than most. Japan was a nice balance of people giving you room to breathe while still being very helpful if they saw you were lost or struggling; I don't expect to be in my comfort zone by any means (because why travel, then?), but it would be nice to visit a neurodiverse-friendly place.

I would be more than happy with both cuisines; I'm fortunate to live in an area with sizable Korean and Taiwanese diasporas, so we have relatively easy access to both. For me, it boils down to cost and quality. Where would it be easiest to get an inexpensive meal, especially as a single traveler? I hear a lot of good things about the night markets and street food in both cities, but I'm curious about restaurants as well.

As for culture, I have heard South Korea is generally more introverted and insular while Taiwan is considered to be more laid back and extroverted, relatively speaking. I'm good with both, but I'd like the opportunity to interact with locals. I am also very interested in exploring traditional culture (IE operas, folk music, art museums, historical sites, etc). I'm less interested in nightlife and drinking than most people my age; I'd certainly try it out, but it's not really a deciding factor.

So far, I'm slightly leaning towards Taipei (the weather and ability to do things comfortably being a big factor). I've researched the two cities independently, but I would love to get some external input from people who have been. Thank you!