what can I do with the transaction-id?
I know in cases like that some people are asking for it,
but I haven't heard of any recovery because of the transaction-id.
Just trying to understand for what it's good or use.
People are asking for the transaction id in order to look at the transaction that sent the coins from your wallet. There may be a clue to where the coins went and even a possibility that you haven't actually lost the coins. Don't hold your breath. If everything you wrote is accurate, then it is probably impossible for you to get your coins back.