It's important to understand that there isn't a universal best on-page SEO score because different tools and platforms use their own criteria and algorithms to assess a page's optimisation level. However, striving for the highest possible score within the tool you're using can guide improvements.
Remember that while achieving a high on-page SEO score is commendable, it's not an end in itself. The ultimate goal of SEO is to improve visibility in search engine results pages (SERPs), drive organic traffic to your site, and enhance user experience leading to higher conversion rates.