Empty Collection pages and their effect on SEO

In my client’s project, we have a Collection with a template we don’t use. We need that Collection to pull data on the modular page, but from there we redirect users to the resource outside the website and not to the template page. I checked in Google Search Console - all those empty pages were indexed. I did a small research and everywhere it says that empty pages are bad for SEO. What can be done in our case? If I create a custom sitemap and don’t include those pages - would it help? It’s not a best solution (if it’s a solution at all) as website very dynamic and they constantly create new content, I’m not sure that they will be able to sustain a custom sitemap. Should I disallow or noindex those collection pages?

Any input will be much appreciated. Thank you!

Here is my site Read-Only: LINK
(how to share your site Read-Only link)

You can include the following meta tag in the Head custom code of any blank CMS pages to prevent them from being indexed:

<meta name="robots" content="noindex">