Creating org-agenda-file-list variable based on filetags

I’m using several custom agendas with “org-agenda-custom-commands”. In order to build a list of files to include for the various agendas am I expanding the org-agenda-files variable with additional files. For example for my “personal” files do I do this: (org-agenda-files (append org-agenda-files-personal))

To generate a list of files for the “org-agenda-files-personal” variable do I run the following:
org-agenda-files-personal (apply #'append (org-roam-db-query [:select file :from tags :join nodes :on (= node-id id) :where (= tag "Personal")]))

It seems to work as expected for me, but now I got a bit curious if anyone of you have similar needs and solve this in some other way? Perhaps there is some more straightforward way?