In Captain America: The First Avenger, during the final one-on-one fight between Captain America and Red Skull, Red Skull says "I have seen the future, there are no flags" to which Cap replies "Not my future!" and continues fighting, leading to teleportation of Red Skull to Vormir.
Having the Tesseract for quite some time, and being aware of Norse mythology (familiar with terms like Yggdrasil, the tree of life, alien tech etc) did he somehow manage to use Tesseract to see the future, or what else was the above conversation about?