seo – The best way to eliminate low quality pages?

We have a website with approximately 5000 pages.

1000 of them have high quality content.
The other part is pretty bad: basically it's about list pages of categories, with basic "generated" content. We have about 20 different descriptions (150 words, with some variables), so their similarities are very high.

We created these pages in 2013-2014, thinking that you can help us get long queue. It worked a bit, since those pages attract around 20% of our users today.

But we realize that these pages may be the reason why the website does not rank as much as it should in the "high quality" pages: compared to our competitors, we have good metrics in the "technical" aspects of SEO . We also have a good internal link (no more than 4 depth levels) and very good high authority backlinks. But we are stuck on page 2, or at the bottom of page 1 for the better.

So we're thinking about removing these pages, but we're not sure how we should do it:

  • Go hardcore, and delete all the pages. 404 everywhere. Or even 410 for those of us who do not want to create content in the future?
  • Delete only the pages that handle less than X Visits to the month, with 404/410.
  • Remove only the pages that googlebot visits less than X times a month 404/410.
  • We could redirect 301 all these pages to your "main" category. Or all of them, or only those that are not classified, or only those that googlebot does not visit often.
  • Keep all pages, but with "noindex" (but would that still use the tracking budget?)
  • Kill the pages gradually: instead of removing 80% of our pages at once, we could eliminate X% every week for a few months?

What do you think is the best way?