Converting query from MySQL V8.0 to V5.6 - mysql

Question

I developed a system based in MySQL V8.0 and, unfortunately, I need downgrade for the most used version in web hostings, that is V5.6.
My queries are almost all like this:
SELECT tb_d.*, id_classification
FROM (
SELECT ROW_NUMBER() OVER(PARTITION BY '1' ORDER BY od_category ASC, $order_by_gp_mid) AS row_final, tb_c.*
FROM (
SELECT ROW_NUMBER() OVER(PARTITION BY id_category ORDER BY MOD(`row` * $prime_group, 512)) AS rd_category, tb_b.*
FROM (
SELECT ROW_NUMBER() OVER(PARTITION BY '1' ORDER BY od_category ASC, $order_by_gp_mid) AS `row`, tb_a.*
FROM (
SELECT ROW_NUMBER() OVER (PARTITION BY id_category ORDER BY od_category ASC, tb_x.$order_by_gp_mid) AS rn_category, tb_x.*
FROM (
SELECT
1, od_category, id_category, `group`, category,
id_post, thumbnail, head, visibility, created_datetime, `view`, yeslike, save,
lk_post_category_pic_uvw.fk_pic,
ROUND((yeslike + total_save) / view, 3) AS rank_ratio
FROM tb_category
JOIN (
SELECT fk_post, fk_category, fk_pic
FROM lk_post_category_pic
UNION
SELECT fk_post, `from`, fk_pic
FROM lk_post_model_pic
JOIN tb_model ON tb_model.id_model = lk_post_model_pic.fk_model
WHERE `from` != ''
) AS lk_post_category_pic_uvw ON lk_post_category_pic_uvw.fk_category = tb_category.id_category
JOIN tb_post ON lk_post_category_pic_uvw.fk_post = tb_post.id_post
LEFT JOIN vw_total_save_by_post ON vw_total_save_by_post.fk_post = tb_post.id_post
WHERE visibility = 'show'
) AS tb_x
) AS tb_a
WHERE rn_category <= 35
) AS tb_b
) AS tb_c
WHERE rd_category = 1
) AS tb_d
JOIN lk_post_classification_pic ON tb_d.id_post = lk_post_classification_pic.fk_post
JOIN tb_classification ON lk_post_classification_pic.fk_classification = tb_classification.id_classification
Being that the variable $order_by_gp_mid can assuming these values:
$order_by_gp_mid = 'created_datetime DESC';
$order_by_gp_mid = 'rank_ratio DESC';
$order_by_gp_mid = '`view` DESC';
$order_by_gp_mid = 'created_datetime DESC';
$order_by_gp_mid = 'created_datetime ASC';
So, the biggest problem here are the lines ROW_NUMBER() OVER(PARTITION BY blabla...).
I need rewrite this queries, and so many others too, for MySQL 5.6.
I already read many topics about here in stackoverflow but, I don't how to do it because my queries are very complexs.
So, I don't know what to do anymore, I'm absolutely exhausted of computer programming.