Pillar pages as a wordpress ‘post’ or ‘page’

Hi there, I’m wondering what is the best SEO protocol for pillar pages in WordPress regarding if they are set as a WordPress Post or a WordPress Page.

The question is this: Can a wordpress page act as the pillar for a group ofposts? Or should it best be a post acting as a pillar to other posts?

I can see from the RankMath blog that USUALLY a pillar page is a ‘POST’ in wordpress. Perhaps this is better because the pillar post also is classified in the same wordpress CATEGORY as all the content posts for that content cluster. And in the category XML site map the pillar post is in the same category as all the cluster posts it’s linking to (because its the pillar content)

This is my concern:
I currently have my pillar pages set as a WordPress Page (because it was easier to make design changes). They are longform guides with links to all the posts for that content cluster (each cluster has its own wordpress category). It bothers me that in the category XML sitemap, that the pillar page is not in the category sitemap for all the posts its linking to (because pages don’t have a category). T

If the pillar page was also set as a post, then it would appear together with all the posts that it’s a pillar for because I can set the category.

So as I said the question is this: Can a wordpress page (act as the pillar for a cluster group posts? Or should it best be a post acting as a pillar to other posts?

Any advice much appreciated. Thank you!