Generating Unsetted Image Sizes ?

Hi,

My woocommerce has a lot of products, so I unset some of the image sizes previously because it causes a lot of unnecessary images and slow website and my ftp program can’t open my images folder,

So I only use 2 image sizes. Default and 300×300.

But an update to this plugin broke this rule in my website, and generated lots of unnecessary images like 50×50 and 100×100, and I am now trying to recover from this issue.

Normally I unset the image sizes with below code in functions.php

add_filter( 'intermediate_image_sizes_advanced', 'prefix_remove_default_images' );
function prefix_remove_default_images( $sizes ) {
 unset( $sizes['shop_thumbnail']); //100px
 unset( $sizes['woocommerce_gallery_thumbnail']); //100px
 unset( $sizes['shop_single']); //600px
 unset( $sizes['woocommerce_single']); //600px
 unset( $sizes['medium_large']); // 768px
 return $sizes;
}

I am not sure how it broke this rule, and how I will fix it.