Question about DLC unlockers.

Can, for example, GreenLuma be used to unlock dlc's on single/coop games like Borderlands? Would i get banned if i'm using this in singleplayer game?

I think Greenluma is detected only by EAC. EAC is used in online games. You can try, but I do not guarantee you will not get banned.

Try to use GLR (greenluma reborn) with nohook parameter and by not replacing the x64launcher