Just some clarification on this one but yes there should be a quest called "The Speaker's Call" that should begin the Artifact Weapon Overcharge. You will need to complete the prerequisite Magni quests in order to receive "The Speaker's Call". When you complete this it should overcharge your artifact up to Artifact Level 126 which puts you at 75 Concordance. All of the existing traits will function until the pre patch.
Take advantage of the overcharge and go take on things like the Mage Tower, Ahead of the Curve: Argus, and The Chosen. Also don't forget the usual Mythic mount drop chances that will be lowered from their guaranteed 100% when Battle for Azeroth goes live!
It should only affect Artifacts that are below that value. So if you're above Concordance 75 it should keep you at that Concordance value. However you might notice it jump up in a week or two ;)
This just simply upon completion moves everyone to Concordance 75 and then next week another bump, and then another. You get the picture.
TL;DR: Smash everything.