I’m not sure I’m really following what you’re trying to explain here - if I’m understanding you correctly the net effect of what you’re trying to accomplish is to render a string - and then using that output as yet another string to be rendered.
Am I close to understanding the root issue? If so, see this response for an idea of how to do that - Using a string as template in CBV - #4 by carltongibson
If I’m not, a more specific example may be helpful to illustrate your question.