Du coup j'ai trouvé la réponse à ma question sur reddit, si jamais certains se pose la même :
" I would say yes. The game in all routes is completely identical in chapters 1-8, even in the true route where you'd expect some differences. There's only a couple scattered dialog lines that change. That said, the game has a skip function you can use to automatically skip text you've read before which combined with the fact that your stats carry over in NG+ means that you can blitz through the first 8 chapters of the game very quickly.
After chapter 8 though the story is completely different in all 4 routes. (The bad ending ends immediately after chapter 8). All four are compelling in their own way, though between the two of us my favorite is Wrath. Personally I advocate doing the 3 non-true endings and then the true ending for your last run, partially because the enemies in the true ending are a lot tougher than the ones in the other 3 endings so saving it for last means you have 3 routes worth of NG+ bonuses to help you out.
And then if you want to see the bad ending at any point... it's just a single choice at the end of chapter 8. Just save and then pick it to see it and then reload your save when you're done.
Oh, one last thing, if you don’t care about achievements or NG+ bonuses… you don’t have to go through the game entirely all four times. When you get to chapter 8, you have the choice between three endings. The bad ending is always available but you can actually choose between your two highest traits for the ending you actually do - it isn’t automatically your highest. Which means if you want you can finish your Harmony run, then play again with an even split between Wrath and Moral, then save the game at the end of chapter 8. You can then use that save point to go into either the Wrath or the Moral end and reload it after finishing one ending to do the other. The only downside is you can’t chain them into NG+ that way. But if you don’t care about achievements then that’s a non-issue. (The achievement to unlock every Digimon is only possible by chaining NG+ through all four routes as some Digimon are only available on certain routes.)
The true route requires its own dedicated run though. It requires NG+ and you get locked into it on chapter 4. Once you’ve met the conditions for the true route, all other routes become locked for that run."
Source : https://www.reddit.com/r/DigimonSurvive/comments/125po16/is_it_worth_playing_every_route/
