Plugin class Smile/ElasticsuiteCore/Plugin/Deprecation/ClientPlugin doesn't exist

In magento 2.4. elasticsearch is required, and it will support for multi selection. We researched and found that you should use smile elasticsearch modules and using smile instead is very essential.

First, please make sure you enabled elasticsmile modules by reading this file "readme.txt"

https://drive.google.com/file/d/1FQDL6_ui40-DpWIr5_6sDwK10W912pQy/view?usp=sharing

Please follow the exact instructions in the readme file