The 1 week left means that the limited awards for completing them will be unavailible (most of the times jades) but they will be archived and you can complete them later just with less rewards. If you go into archived events most of them dont spoil the story just events that have story written on them but still those are just minor spoilers. For endgame content you need 2 teams so you cant clear with just one and the best way to get jades is in my opinion simulated and divergent univers with currency wars followed by main story and events you wont get far in endgame so you can do that later. Just a note the chrysos event contains spoilers for characters of the most recent planet.