Well, remember that the story is still yours. How many bank robbery or love stories have been written? A gajillion! I just counted. Anyway, the point is that the plot twist you come up with is almost guaranteed to not be some new idea that no one on the planet has ever conceived of. Nope...no offense. Plus, the plot twists often don't give all the details. Here are 3 examples:

The leader of a band of mercenaries is hired to find a missing person who turns out to be the long lost heir to the throne. The mercenary discovers that they are the very person they were hired to find.

The hero burst into the throne room of the dark lord only to find the dark lord crying his eyes out on the damsel’s shoulder.

The knight rescues the princess from the dragon only to discover she was evil.

So, maybe you like the idea of #3, but don't have dragons or princesses in your story. No worries. There's probably someone being saved from something--drowning, bad relationship, lack of education, etc. Make that person terrible and the person helping to save them now questions if saving them (or helping them) was really the right choice. Maybe they "saved" them from a bad job and helped them get a job helping kids only to realize they are terrible and are only in it for the money and don't care about the kids at all.

I'm just saying, you don't have to use the idea word for word and while it's great to come up with your own ideas, don't feel SO PRESSURED to do it. Try. If you can't get your own ideas to come forward and work, browse the Adopt a Plot Twist thread. Sometimes it's not even that idea, but it spawns a new idea for me.

Just suggestions and resources. Do with them as you please.