There's a lot of shit on this forum, no one knows anything.
Soon I will prove to you the tx efficient method
You acting desperate is why no one will trust you, and especially with 6.7btc($700k).
make a tx with an absurdly low fee and publish the private key here after transmitting it, if nobody manages to replace it, you will have credibility.
Just like @mcdouglasx told you, do this and if no one here could intercept it, then we will all trust you