I have enabled Facebook Instant Articles and have connected my WordPress site with my Facebook page. Is there a way to disable this connection to post articles like before completely or can this be performed for a section of articles which I want to publish normally without Instant Articles?
To remove instant articles you need to:
Remove the meta properties tag from your page. To enable instant articles, you installed a tag like this:
<meta property="fb:pages" content="123456789" />
Go to the instant articles configuration on Facebook and remove your URL. Here is a Facebook help center page that tells you how to get to it: https://developers.facebook.com/docs/instant-articles/guides/publishertools