According to the materials I had looked up in the Luoshan Office, some bizarre phenomena do indeed allow one to travel between the past and the future, but they are supernatural occurrences that are absolutely beyond the capability of human recreation and are also rare experiences that can be encountered but not sought after.
The extent of Luoshan's assertion that such occurrences are "unreplicable" and "cannot be sought after" became clear when I looked at their publicly available data repository. The ritual knowledge related to time travel was brazenly laid out for all to see, and in summary, it read, "I followed the steps below and successfully traveled to the past and future, but for some reason, I am always unable to succeed afterward, so I'll just leave it here, believe it or not."