(Ripped directly from my post on the talk page in the Timeline page.)
Recently, I did research on the timing of HZD and HFW, and I posted that research on Reddit. My research indicates that it is more plausible if this wiki's timeline reckons HZD and HFW to have taken place in 3039 and 3040, respectively, instead of the 3040 and 3041 it reckons currently. I refer you to my Reddit post for my complete argument, especially Entries 21 and 32, but to drive the point home, I'll take an excerpt to explain why that should be the case.
Take the Reactor Report datapoint in HFW. It says that at the time of Aloy's entry into Thebes, the bunker's reactor had been operating for 50,844 weeks. It is unknown when exactly the reactor came online, but bounds can be placed to narrow the possible dates. From the NDA Motherload datapoint, construction of the bunker did not begin until a few weeks after Ted Faro learned that the apocalypse was coming, in November of 2064. That reactor likely also came online sometime before Faro killed the Alphas (February 2, 2066, from a conversation with GAIA at the Base). Most likely the reactor came online around the time the atmosphere went bad for humans, which would be November 2065, but that is beside my point. Even stretching things to the edge of implausibility (by fixing the date the reactor came online to February 2, 2066), that yields a no-later-than date of July 14, 3040 for Aloy's quest at Thebes. Given that the "Faro's Tomb" quest happens late in the game, this would be a pretty good case for HFW happening in 3040. I cannot think of any other plausible explanation to push that date further to 3041, as the timeline reckons. Aloy had a six-month abscence from Meridian between HZD and HFW, so even by implausibly assuming that Aloy went to Thebes the moment she left Meridian after the quest at the Spire, that only takes her back to as late as January 3040 for when she left Meridian after the Battle of the Alight. Given HZD's expanse, this also means that very likely HZD takes place in 3039.
I do realize that this would impact the reckoning of Aloy's and other's age in the series, but I'll leave it at that for now.
What are your thoughts about making the change to the timeline so that the events of HZD and HFW are said to take place in 3039 and 3040, respectively?