Oh why... when will people learn to read T-T
Here is a more cut down detailed translation.
「DLCの物語に関しては、本編で描かれなかった部分を描くだけではなく、プレイヤーの遊び方によって結果が変わっていくようなものも予定している。
In regards to the story of the DLC, it will not just depict what wasn't depicted in the original story, but there are plans to implement something like where the players playstyle will change the outcome.
あくまで本編の物語を変えるものではなく、DLCであればこういう方向でも楽しめる、というような幅を持たせたい。」
It must be said it's something that will not change the story of the original story, but we want to allow people to have this kind of freedom, where as a DLC you can enjoy it in this kind of way.
Going over the specific line. あくまで本編の物語を変えるものではなく - akumade honpen no monogatari wo kaeru mono de wa naku
あくまで - akumade - This is kinda of a difficult word to translate, but it can be translated into as 'nothing more than'. Example ''akumade watashi no iken desu'' would mean ''it is nothing more than my own opinion''.
本編 - honpen - Means ''original story'', in this case it refers to the original game.
の - no - Possessive particle, example combined with ''honpen no'' would be ''the original story(s)(stories)''
物語 - monogatari - Means ''story''
を - wo - This particle indicates the topic before the action.
変える - kaeru - ''To change'' or ''to alter''.
もの - mono - ''Thing'' or ''object''.
ではなく - dewanaku - Simply ''is not'' or ''it is not''. Example ''puromuto wa ouzoku dewanaku, shimin desu'' - ''Prompto is not of royalty and is a commoner''.
Typical amateurs...