With all due respect, you are not taking advantage of opportunities to gain exposure.

You have an Amazon Author's page, but it only shows one book. If you have more books that can be purchased via Amazon they should appear on your author's page.

I am not an author, but I have seen others do this on Medium. You are allowed to share links to your books via your profile page. Look at this profile as an example: https://medium.com/@aliwritesaz

Is LinkedIn the only network where you are active? If you are on Twitter, Facebook, etc., you should share all the ways to connect with you.

Do your best to grow your presence here on Medium. It is one of the best platforms for writers and authors.

I also have don't earn easily for my online work. But I do earn. It takes persistence and perseverance.

I hope my comments are of some help to you. Wishing you success!