Varchar(MAX) in SQL Endpoint

I'm testing VARCHAR(MAX) support in a Fabric Lakehouse SQL Analytics Endpoint and discovered that it only worked after:

1. Enabling New Metadata Sync (Preview)
2. Creating a new Lakehouse after enabling the setting

Existing Lakehouses didn't seem to pick up the capability.
Is this officially expected, or is there a migration/upgrade path for existing SQL Analytics Endpoints?