Too bad you couldn’t do something open source like that since it requires the D&D licensing.
You don't have to use any d&d system or content to make something similar (tho tbh I don't think it's a good system for videogames anyway), but especially on the content side it's hard to find a team dedicated enough and founds enough to make it happen
To my understanding it's one step more, not only observation but interaction as well, manipulating one side of the entangled particles resulting in an instant (and similar/same) change on the other side as well. In fact even the observation is a form of interaction in this case that changes the state of the entangled system.