How to increase product variation limit in woo commerce?

Hello

Now I have 575 products and every one of them have 170 variations.
When I create 171 variation the product breaks and show all variations. When I delete one variation and 170 variations remain, everything is fine and the variations are displayed correctly.
I obviously have a limit to 170 product variations.

I tried that:

1. I increased the parameters of “max_input_vars” from PHP to 80000, but there was no result.

2. I increased the value of “woocommerce_rest_batch_items_limit” from 100 to 300 from (wordpress/plugin/woocommerce/includes/abstract/abstract-wc-rest-controller ) but there was no result.

3. I put these codes in my child theme in function.php but there was no result.

a)

function custom_wc_ajax_variation_threshold( $qty, $product ) {
	return 300;
}
add_filter( 'woocommerce_ajax_variation_threshold', 'custom_wc_ajax_variation_threshold', 100, 2 );

b)

add_filter( 'woocommerce_ajax_variation_threshold', 'ww_ajax_variation_threshold', 10, 2 );

function ww_ajax_variation_threshold( $default, $product ) {
	return 150;
}

I use WordPress 5.2.2 and Woocommerce 3.6.5.

How to increase product variation limit in woo commerce or I have another problem and how can I fix it?

Best regards,
Nikolov

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