I was thinking and I think it would be interesting if the Created found the SoF instead of the UNSC. The created seem to have control over the forerunner forces and probably know about all the locations of forerunner stuff such as the ark. Cortana might hear about the conflict there and go to it to see if it is the Infinity but find out it isn’t. If she finds them she could get Seriana to join her and lie to the crew about how the war ended and tell them that the war ended the human race.
This might seem far fetched but it may happen as they probably want to set up Halo 6 or something.
Sorry for any errors in spelling.