TJ is written in a way that's more attractive to the younger audience. Badass, super possessive, kinda gloomy, etc... that's why he's so popular.
Jo is simply the more rational option, selfish or not. He was the MC's only ticket to a normal life. And he was actually a decent guy. Flawed, but decent.
And your memory is correct, TJ did force himself on MC/coerced him into it, use violence, threaten him, lie to him, and he hired thugs to hurt him so he couldn't compete in some race he was preparing for. And even after that, after the MC's leg got fucked permanently, he used his guilt as an excuse to not be honest about it AGAIN because "they weren't supposed to go that far".
All that being said, it kinda makes sense that TJ would be the endgame. They have history together. They have a fucked up relationship, but Jo doesn't have the depth of character to stay with him. He needs someone at least half as fucked up as himself.
What happened for people to call Jo selfish or just hate him? Like I remember Jo being normal to me and Tj being somewhat of a yellow-red flag. I only read the beginning and just forgot abt it and never finished it. What does Tj do to even warrant such a fanbase cause I might be getting this confused with something else but I thought he forced himself onto the mc? Is it worth reading?