100% the game has to end depressingly, cuz the message should be like, if you went through shit you couldn't control in your past life, why would you be able to in a new one? fr. You're not some god to take down a huge mafia with crazy connections, you're not some lucky guy who got a second chance to fix everything. You're a loser who got a second chance just to prove you still couldn't do anything no matter how hard you tried. The main character literally asks at the start, "Could I fix my past life's mistakes?" and the answer has to be NO.
Tbh, I don't want a good ending in the game, because that'd be boring. I see two ways it could go: first, where all the MC's friends die and he dies too, just like in his past life, which would be pretty ironic. Or second, where some NTR happens and the MC dies, showing that even if you had 400 chances, you still couldn't do anything in a situation you were destined to lose from the start. imo.