Nodes not get indexed after running manual cron
To turn off delayed indexing, navigate to the /admin/config/search/search-api page then click on the 'edit' button for the index.

On that page, at the very bottom, just above the Save button, there is a collapsed panel titled 'INDEX OPTIONS'. Open the panel and it should look like this.



This is where you can control whether indexing is immediate and the cron batch size.