Then the blochain of the "hacker" will have 1 block more than the others, thus it should be, at least for a few minutes, the "valid" blockchain
This is incorrect. A block that contains an invalid transaction is invalid, period.
The network's rule is that the longest(*) valid chain is the one to be treated as correct. A chain with any invalid blocks in it ...
This is either a scam or it's not. It's very easy to tell which:
Case 1: There are no actual signals that make a profit. In this case, it's a scam. Case closed.
Case 2: There are actual signals that make a profit. In this case, who cares whether it's a shady exchange or not? You have the signals -- trade larger amounts on a legitimate exchange, never try ...
Your best bet is to report to the proper authorities.
Contrary to popular belief, Bitcoin transactions are in fact traceable. There is a slight chance that the scammer(s) proceed to make a mistake and withdraw the BTC you transferred in a way that sheds a light on their identity.
I'm sorry for your loss. As a 'tech person' reasonably informed about cryptocurrency, I concur that it is highly unlikely that you will ever recover any money.
Some information about Bitcoin and online scams
Technically, it is not hopeless though. You recovering (some) money would hinge on this chain of events:
It is not completely impossible that the ...
How do I recover from a cryptocurrency scam?
You don't. At least, you don't recover your money. I guess you recover by learning from the mistake and doing things more safely in future. It may be worth asking an accountant if the financial loss on your investment can be offset against other taxable income.
I contacted my bank to see if they could do ...
Short of having law enforcement and the legal system whose jurisdiction the scammer(s) reside in compelling them to return the funds, you are out of luck.
Bitcoin transactions are irreversible. Once they have the coins in addresses for which you do not own the keys, there is nothing you can do to recover them.
Your only option may be to treat this as an ...
Is there any software or organization that can verify whether wallet is secure or not?
You can use an open source wallet and take the time to read and understand all the code and then compile it yourself. This would be an unfeasably large task for most ordinary people. Software developers might find it a bit easier but it is still a large amount of work.