How can we safe ourselves from well organized scam projects? Some projects are so well crafted and in the end they scam people, to my own understand research doesn't help here at all, use case, whitepaper, team, every thing are so real and make sense, please give advice about this
Extensive research. Not just the kind of research wherein you're just scanning the project/startup's website and not doing extensive background search.
You need to look past the wonderful looking website, the listing promises to a prominent cryptocurrency exchange and even to how well-known the team behind such a project is.
Dig deeper until you find some red-flags. Avoid getting lured in with the "nice things" others may say about the project/company; you'll have to do your assessments on your own.
If everything checks out then you may jump-in, but remember, invest only what you can afford to lose.
Not many people are prepared to go into that stress of the kind of research you are asking for here. I know it is very easy for you to do as a bounty manager because if you do not do a thorough research and you make a contract with a scam project, everybody will accuse you of knowingly promoting a scam. This will affect your reputation here. But not many hunters and investors care about all that and they may not have that time for a vigorous research.