Google indexed, permanent removal

I have a few pages in WP that do not make sense and I filed a bug.
A category equals negativ one

So I did a quick fix
robots.txt
Disallow: /de/page/27/?cat=-1

Now in google search console I get: Indexed, though blocked by robots.txt

Then I found the following article:
https://support.google.com/webmasters/answer/9689846?hl=en
where it states: do not use robots.txt
use
Remove or update the content on your site (images, pages, directories) and make sure that your web server returns either a 404 (Not Found) or 410 (Gone)

Is this possible with your redirection plugin and what would be the setup?

thanks

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