In my opinion you don't really need any tools for this. You can simply follow a checklist for your on-page SEO.
Here's a simple checklist that can be useful:
1. Proper content format/structure with H1, H2, H3s in bold
2. Focus keyword in URL and make it super-simple
3. Alt tags for images
4. Keyword in SEO title
5. Keyword in SEO meta description
6. TOC - jump links, anchor links for article sitelinks appearance in search results page.
7. Tech SEO - Schema markup (FAQ, listicle, How-To, Q&A...), image compression
8. Submit URLs in search console, add the URL in sitemap
9. Interlink to and from other relevant pages
10. Win featured snippet position: For paragraph snippet have a clear-cut answer with 40-50 word, within 300 characters.
11. Make sure your content type & format and are in-line with current SERP.