Plugin Not Found Exception
Could you try these steps


drush cex -y actual configs.
Find in your config folder yml file rest.resource.{YOUR_RESOURCE_NAME} and delete it.
drush cim -y this change, it will be correctly removed from DB.
drush cr for sure, and error will miss.


Some related discussion going here 
https://www.drupal.org/project/restui/issues/2889860