Definitely team Suho. I have no idea about the webtoon and I don't care, based on the drama alone, they have great chemistry, they have similar tastes in reading and movies, they have supported each other, they both need to let go of their fears and the unhappy past, and they both need each other to do that because they give each other strength. Plus he doesn't even care about her appearance without makeup, it's truly her personality that drew him in.
I honestly don't see why I should ship her with Seo Jun when the only thing they've got going on is some nice sibling-like camaraderie. I ship them as friends, the way I ship Seo Jun with Suho as friends and truly wish for them to be best friends again and get over the past.