According to Google, both are documents no difference between a page and a post. The only difference is the URL. If it is a post, the URL will be abc.com/blog/page1, and if it is a page, the URL will be abc.com/page1. Other than that, there is no difference. According to Google, both are documents.
If your website is a business or service website, create pages, not posts, because posts are connected to the blog section and create a flat structure. If you create pages, you can keep the structure organized.
Themes: Remove unused themes so that the load on the database does not increase.
Plugins: Keep only the plugins that are being used. Delete the rest of the plugins.
Media Files: Only the images and files that you use should be here. Delete all the remaining media.
Meta Title: The brand name should always be included in the meta title.