Final Fantasy XIV’s Patch 7.58 introduces same-region player matchmaking to North American and European data centers. The change is detailed in the official Patch 7.58 announcement, though the announcement does not spell out the matchmaking system’s specific mechanics or scope.
The patch also includes adjustments to the Crucible of the Unbroken. The particular changes are not described in the announcement, so there is no basis yet to characterize them as a difficulty reduction or a broader rework.
For AAC Heavyweight Tier (Savage), Patch 7.58 strengthens the Echo effect, adding a separate encounter-related change alongside the matchmaking update.