Sadly fire investigators disagree with your methods of determination. But hey internet scholars who just repeat themselves over and over again in the face of evidence are so much more informed. It says a lot that you are just parroting BS you read online.
Look at the pictures...the steel beams are literally melting...no body needs to tell me anything. It's all in the pictures. It's ok...it really is ok to open to alternative theories, I feel you may have a chance of doing so.