Hope you'll find the best solution!
I don't think so that his Idea was fully copied since he stated that his project is not yet started so no one can ever touch his whitepaper except him. I believe that his idea is too common that's why it was taken too by others.
My suggestion to OP is if the market of your idea is still in demand then proceed as competitor but if it's too saturated just like e-commerce, loan and etc then back out and take another course. There is so many ideas that still not discovered that fitted on blockchain.
There are identical project has been running right now so I don't think there's something wrong to pursue that idea, But we make sure that we can implement it so that the people will see and choose to use the service we provide. And if there's someone will exist who's the same with us? well let people go decide on which service provider are good and which is not.
That would be the best solution imo. Great ideas come to mind of different people almost simultaneously since the beginning of times. But the one who can explain it the best and who can bring it to life is the winner. OP shouldn't worry about whether his idea is stolen or not, but should rather concentrate on implementing it.