The optimization process and recommendations:

1. Avoid Calling Functions With Indexed Columns (query line: 28): When a function is used directly on an indexed column, the database's optimizer won’t be able to use the index. For example, if the column `direccion` is indexed, the index won’t be used as it’s wrapped with the function `dbo.fn_LevenshteinDistance`. If you can’t find an alternative condition that won’t use a function call, a possible solution is to store the required value in a new indexed column.
2. Avoid Calling Functions With Indexed Columns (query line: 28): When a function is used directly on an indexed column, the database's optimizer won’t be able to use the index. For example, if the column `NOMBREVIAIU` is indexed, the index won’t be used as it’s wrapped with the function `dbo.fn_LevenshteinDistance`. If you can’t find an alternative condition that won’t use a function call, a possible solution is to store the required value in a new indexed column.
3. Avoid Correlated Subqueries (query line: 32): A correlated subquery is a subquery that contains a reference (column: direccion) to a table that also appears in the outer query. Usually correlated queries can be rewritten with a join clause, which is the best practice. The database optimizer handles joins much better than correlated subqueries. Therefore, rephrasing the query with a join will allow the optimizer to use the most efficient execution plan for the query.
4. Create Optimal Indexes (modified query below): The recommended indexes are an integral part of this optimization effort and should be created before testing the execution duration of the optimized query.

Optimal indexes for this query:

CREATE INDEX acopioci_idx_idcut ON ACOPIOCI (IDCUT);
CREATE INDEX cut_idx_idcut ON CUT (IDCUT);
CREATE INDEX tvc_idx_idtvc ON TVC (IDTVC);
CREATE INDEX viacu_idx_idviacu ON VIACU (IDVIACU);
CREATE INDEX viaiu_idx_idviaiu ON VIAIU (IDVIAIU);
CREATE INDEX registrosimportado_idx_cut ON registrosImportados (cut);

The optimized query:

SELECT
        registrosImportados.id,
        TVC.NOMBRETVC,
        VIACU.NOMBREVIACU,
        CUT.GLOSA,
        registrosImportados.direccion,
        dbo.fn_LevenshteinDistance(registrosImportados.direccion,
        VIAIU.NOMBREVIAIU,
        5) 
    FROM
        ACOPIOCI 
    INNER JOIN
        TVC 
            ON ACOPIOCI.IDTVC = TVC.IDTVC 
    INNER JOIN
        VIACU 
            ON ACOPIOCI.IDVIACU = VIACU.IDVIACU 
    INNER JOIN
        VIAIU 
            ON ACOPIOCI.IDVIAIU = VIAIU.IDVIAIU 
    INNER JOIN
        CUT 
            ON ACOPIOCI.IDCUT = CUT.IDCUT 
    INNER JOIN
        registrosImportados 
            ON CUT.CUT = registrosImportados.cut 
    WHERE
        dbo.fn_LevenshteinDistance(registrosImportados.direccion, VIAIU.NOMBREVIAIU, 5) = (
            SELECT
                MIN(M.DISTANCIA) 
            FROM
                (SELECT
                    dbo.fn_LevenshteinDistance(registrosImportados.direccion,
                    VIAIU.NOMBREVIAIU,
                    5) AS DISTANCIA 
                FROM
                    ACOPIOCI 
                INNER JOIN
                    VIAIU 
                        ON ACOPIOCI.IDVIAIU = VIAIU.IDVIAIU 
                WHERE
                    ACOPIOCI.IDCUT = CUT.IDCUT) AS M) 
                AND ACOPIOCI.IDCUT = CUT.IDCUT