The first thing: I FREAKING KNEW IT WASN'T JUNGKOOKIE! Sorry, I just had to let it out
Second thing: I played a little detective and read the whole story again while taking notes on the clues. And guess what? Now it all comes together! the clues are in the thread https://twitter.com/BabySuga369/status/1248388044291330055

1st one: Obviously it is someone who knows all of them, because the only other option is a very skilled hacker 2nd one:Tae's attitude is exactly like the ES's "People are getting what they deserve"

3rd one: when Tae got to know about Minjee reporting Jackson to the police, ES immediately tweeted about it 4th one: only one tweet with trackable IP, which turns out to be JK's phone, whether the rest tweets has untrackable IP seems too good to be true

(maybe someone borrowed his phone to send a tweet?? that would mean it is one of his friends) 5th one: ES calling Y/N a sweethart and saying "till tommorow" 6th one: "I'll do all your friends and save you for last", but later on when mentioning Y/n's friends it skips Tae

7th one: ES reveals more than 1 JK's secret (as the pattern was 1 secret per person) and reveals Sope to the world - I think it's because they are angry at Y/n and want to get to revealing her secret faster + why would he reveal more about JK?

I assume it is bc this person is mad at him 8th one: when revealing JK's secrets ES also said "too bad you'll naver have her"

After analyzing those clues, my assumption would be it is Tae (my bet - 95%) or it is someone trying to make it seem like it's him