seo – Should I use a canonical link that refers to the current URL of a pagination?

I know that there are similar issues. But that was not what I was looking for OR I did not quite understand them, that's why I'm asking the question here.

My situation

For now, I'm using rel prev and rel next as pagination.

I am also currently adding a canonical link referring to the first page, namely:

The problem

The fact is that the first page contains only 20 elements (like all other pages).
With this canonical link only, the first page is indexed by Google.
I would like all pages to be indexed because important content is lost in these pages.

Should I just change the canonical link to the current URL? that is the current page, in this case:

Or should I do something else, if so, then what?