My observation. The reference paper indicates Earth's LOD was 21 hours 2 billion years ago. Spinning at the equator then about 0.53 km/s. Other reports using strata indicate a shorter day and faster spin rate too at 1.4 billion years ago. 18 hour day with the Moon orbiting about 340,900 km away, thus a lunar period < 23 days. Thank the moon for Earth's lengthening day, https://www.sciencedaily.com/releases/2018/06/180604151200.htm
My note. The Moon about 340,900 km distance from Earth 1.4 billion years ago indicates a lunar orbit < 23 days and distance in earth radii about 53.4 earth radii compared to the lunar mean near 60.3 earth radii distance today. Such changes to Earth's LOD and lunar orbit need to be verified accurately to be accepted as a factual measure of long age or deep time. The NASA ADS Abstract is Proterozoic Milankovitch cycles and the history of the solar system, https://ui.adsabs.harvard.edu/abs/2018PNAS..115.6363M/abstract
, May 2018.
The new article posted here indicates a 21 hour LOD for Earth 2 billion years ago vs. 18 hour day 1.4 billion years ago with a much shorter lunar month too. Some tweaks may still be needed as well as validating the geologic strata for the needed cycles and changes to show evidence for the shorter day and shorter lunar month.