Run these checks in the order a visitor would hit problems. First confirm the site loads over HTTPS without a not secure warning, then submit every form yourself and confirm the message actually arrives in the inbox, not just that a success message appears.
Next, check how the site appears outside your browser: search indexing, page titles and descriptions, and the preview card when a link is shared. The noindex and robots guide and the builder-specific SEO checklists explain which setting controls each one.
Last, decide what you collect. If you add analytics, a signup form or email capture, read the privacy policy guide and the analytics options guide together so your disclosures match what the site actually does.