You can only look back to when light first appeared in the universe, which appears to be 13.? billion years ago. Nothing to look at before that no matter how powerful the telescope.
I get that, suppose at some point it’s discovered that those assumptions are wrong.
I believe there is no end to discovery and knowledge and what our understanding is now might not the same at some point in the future.
Couldn’t a sophisticated enough device image infrared emitting clouds long before fusion reactions begin star light?