Exporting only one filetag

I really want is to figure out how to only export files that have a specific #+filetag:.

I’m following the wonderful work over where they figured out how to export with backlinks.

I experimented with publishing options but found that the output from exporting backlinks (above) ignores the org-publish-project-alist settings for SELECT_TAGS and EXCLUDE_TAGS, so my references contain unwanted data in around other id links. It also exports every file in the :base-directory, I only want the files that have the correct #+filetags:

Here is what my export looks like:

(setq org-publish-project-alist
         :base-directory "roam/"
         :base-extension "org"
         :makeindex t
         :select-tags ("export")
         :exclude-tags ("noexport")
         :publishing-directory "~/public_html/"
         :recursive t
         :publishing-function org-html-publish-to-html
         ;:auto-sitemap t
        ("all" :components ("roam"))))

I can suppress certain parts of the org-file with :export: and :noexport: but not in the references.

How would I write a batch export to only export files matching a #+filetags: or contain a :tag:? I remember seeing that in V1 people were blogging but excluding a :private: tag. Is there something similar in V2?