Starting with Magento 2.4.0, it’s recommended to install all the extensions via Composer.
→ Magento advises to backup your DB and enable the maintenance mode before taking any further steps.
$ composer require <component-name>
e.g.: $ composer require amasty/shopby
$ bin/magento module:status amasty/shopby
$ bin/magento module:enable amasty/shopby
Module is enabled
$ bin/magento setup:upgrade
$ bin/magento setup:di:compile
$ bin/magento cache:clean
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