I personally would prefer TJ and Ian to have a happy ending, where they could communicate better and love each other without all that heavy world they've lived in and made mistakes in.
And I would prefer Joseph to distance himself from Ian, since I feel he's a noble character and deserves better. Not to have the worst of him brought out in that spiral of conflict, a victim of Ian's broken heart.
Regarding the possible ending with TJ's death, that would devastate Ian and he might do something suicidal if he were alone.
...but I suppose that's what Joseph is for. Without TJ and with a broken Ian, Joseph is probably the only one who can save him from that world and from letting himself die. Help him with his grief, perhaps.
Even though it's a tragic ending, and I wouldn't like TJ to die, I still feel like it seems to be heading in that direction. If the creator puts Ian at risk, I feel it's likely that TJ will get himself killed to protect him.

I suspect the creator might end up killing TJ to save Ian. Even though he chose the mafia as his world, he loves Ian and I don't think he'd let them kill him. So the creator could use TJ to save Ian and give him the freedom he desires, possibly alongside Joseph.
Besides, seeing how much Ian loves TJ, it's unfair to Joseph that he's with him like this. Jo deserves better, and Ian has many unfinished feelings and resolutions with TJ. Killing TJ and giving him his freedom is what I suspect the creator might do. For me It's sad, but it seems the most viable outcome.
Jo's death would be an injustice. Ian's death would be a tragedy for everyone involved. TJ's death saving Ian...would prove that Ian was indeed what he loved most, and that Ian could turn the page on that whole world with Joseph, who would be the most suitable partner.