System table data is available at the account level. If you are trying LH Federation for querying system tables isn't that already available in the source workspace?
https://docs.databricks.com/en/admin/system-tables/index.html#what-are-system-tables
https://docs.databricks.com/en/admin/system-tables/index.html#enable-system-table-schemas
Since system tables are governed by Unity Catalog, you need to have at least one Unity Catalog-enabled workspace in your account to enable and access system tables. System tables include data from all workspaces in your account but they can only be accessed from a Unity Catalog-enabled workspace.
System tables are enabled at the schema level. If you enable a system schema, you enable all the tables within that schema. When new schemas are released, an account admin needs to manually enable the schema.