For the sake of completeness, I will note, it is fully impossible. Technically you could create a contiguous line by placing tens of thousands of tiny. circles in a formulaic fashion using nested repeat zones. Performance costs aside, which would be beyond slow to the point of unfathomable, this could not be in any way procedural in the sense that you’re using. Shader nodes are stateless, and you can’t have continuity and psudeo-randomness at the same time in a stateless environment. Any perceived continuity would be an coincedental example of the lamp post principle. Making continuous connected randomized lines would be the same as Monte Carlo sampling- throwing millions of nails on the floor- and expecting them to form scribble lines. Even if it did happen once, it couldn’t definitionally be reproducible a second time.
All that is to say- grab some wave textures, distort them, layer them, randomize their rotation, etc, and see if that gets you close enough