It is similar to the Page-Wootters mechanism (although they assume a global state). It was actually one of my main insights that led to this theory, how time could emerge. I had this realization thinking about the heat death of the universe and how there will be no reversible processes to be able to operationally track time. Then I realized that it would be similar to how all clocks become just random noise at the event horizon from the point of view of an external observer.