Rank is dropping. Should I create new content using the same keyword or upgrade it?

Hi. I'm new to SEO.

I have a page based on certain keyword that is used to be rank 1 in Google search result.

After some weeks, it dropped to around rank 30.

My goal is to rank again using this keyword.

What should I do to this content?

Should I create new content using the same keyword or just upgrade it?

Thanks

Digital marketing agency in darbhanga