Another possible endogenous end point that could be advanced is meeting (or being detected by) an alien (or alien AI) civilization earlier and having our civilization destroyed by them earlier as a result.
Or maybe we enter an astronomical suffering or hyperexistential catastrophe due to conflict or stable totalitarianism earlier (internally or due to aliens we encounter earlier) and it lasts longer, until an exogenous end point. So, we replace some good with bad, or otherwise replace some value with worse value.
Another possible endogenous end point that could be advanced is meeting (or being detected by) an alien (or alien AI) civilization earlier and having our civilization destroyed by them earlier as a result.
Or maybe we enter an astronomical suffering or hyperexistential catastrophe due to conflict or stable totalitarianism earlier (internally or due to aliens we encounter earlier) and it lasts longer, until an exogenous end point. So, we replace some good with bad, or otherwise replace some value with worse value.