This module for Magento 2 makes unlinking categories from products 1000 times faster. The problem is described here:

• #18144: «Detaching category from product causes massive product url regeneration»
• #7874: «OOM/Timeouts when saving a category with large catalog as all product URLs are regenerated»

How to install

bin/magento maintenance:enable
composer clear-cache
composer require mage2pro/fast-unlink-categories-from-products:*
bin/magento setup:upgrade
rm -rf var/di var/generation generated/code && bin/magento setup:di:compile
rm -rf pub/static/* && bin/magento setup:static-content:deploy en_US <additional locales, e.g.: de_DE>
bin/magento maintenance:disable

How to upgrade

bin/magento maintenance:enable
composer clear-cache
composer update mage2pro/fast-unlink-categories-from-products
bin/magento setup:upgrade
rm -rf var/di var/generation generated/code && bin/magento setup:di:compile
rm -rf pub/static/* && bin/magento setup:static-content:deploy en_US <additional locales, e.g.: de_DE>
bin/magento maintenance:disable

If you have problems with these commands, please check the detailed instruction.