I have 270 k product in my store. Now I want to create CSV and send to Google feed by custom script, how to achieve this in Magento2.
Since you have a lot of products , the best extension for that is Xteno Magento Product Feed Export Module Link . I have installed this , tested this and it provides the templates generated in magento 2 admin for product feed also the export as csv option in your case . You can read more on the link i showed you .