If you are familiar with Magento DB structure for reviews, I would recommend using raw SQL.
For example:
-- Edit values
SET @PRODUCT_ID = 123;
SET @STORE_ID = 1;
SET @CUSTOMER_ID = NULL;
SET @REVIEW_TITLE = 'Lorem Ipsum';
SET @REVIEW_DETAIL = 'Neque porro quisquam est qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit...';
SET @REVIEW_RATING = 5; -- Between 1 to 5
SET @REVIEW_NICKNAME = 'John Doe';
SET @REVIEW_CREATED_AT = '2019-07-15'; -- OR date in YY-mm-dd HH:ii:ss format
-- No need to Edit
SET @REVIEW_ENTITY_ID = (SELECT entity_id FROM rating_entity WHERE entity_code = 'product'); -- 1: product, ...
SET @REVIEW_STATUS_ID = (SELECT status_id FROM review_status WHERE status_code = 'Pending'); -- 1: Approved, 2: Pending, 3: Not Approved
INSERT INTO review SET created_at = @REVIEW_CREATED_AT, entity_id = @REVIEW_ENTITY_ID, entity_pk_value = @PRODUCT_ID, status_id = @REVIEW_STATUS_ID;
SET @REVIEW_ID = (SELECT LAST_INSERT_ID());
INSERT INTO review_detail SET review_id = @REVIEW_ID, store_id = @STORE_ID, title = @REVIEW_TITLE, detail = @REVIEW_DETAIL, nickname = @REVIEW_NICKNAME, customer_id = @CUSTOMER_ID;
INSERT INTO review_store SET review_id = @REVIEW_ID, store_id = 0;
INSERT INTO review_store SET review_id = @REVIEW_ID, store_id = @STORE_ID;
INSERT INTO rating_option_vote SET option_id = 5, remote_ip = '', remote_ip_long = 0, customer_id = @CUSTOMER_ID, entity_pk_value = @PRODUCT_ID, rating_id = @REVIEW_ENTITY_ID,
review_id = @REVIEW_ID, percent = 100, value = @REVIEW_RATING;
For details on how to "Import Product Reviews in Magento via SQL", please visit
https://blog.magepsycho.com/import-product-reviews-in-magento-via-sql/
