In that lens, there seems to be two obvious paths: expand to new planets or climb the Kardashev scale and use your limitless energy to recycle every atom.

As long as you can get to one of those stages before you run out of the required industrial capacity you should be fine.

If we absolutely had to, I think the human species could moonshot our way to either fusion or asteroid mining inside a couple decades. At least with our present resources, maybe not in a century from now.