I am 33 so my way of thinking is different from yours and I speak from experience thank you very much!!
I prefer toxic men in my manga's and lots of smut and sex. I have nothing against the fluffy shit but I like to keep it to a minimum as I already have my own fluffy relationship thanks! lol.
Both of love them are fixated on the past and need focus on the future. Both are selfish and both need to zbe up front and 100% honest. That's all Jooin wants.
He can't choose because they both hide things..be sweet and hide things again. Whether one was toxic and the bother wasnt.. doesn't change they both are not 100% honest with Jooin. Whoever he chooses I hope he's happy. Thats all.