For a keyword of 5k demand I am lready ranking at 4 or 5th position

[vk_lord]

You haven't mentioned the age of your domain. The domain authority also matters and if your domain is new then users will take time to scroll down and click on your keywords, this will tell the google that your site is useful. Also, don't forget to create backlinks.

Domain age doesn't matter in today's world.

And talking about DA, why google would care about a third party metrics? No to mention which is highly inaccurate.