What ratio of internal to external links is normal on a page?
There isn’t an ideal ratio. What is ideal is the authority and relevance of the links you gain and that you internally link to your main, important pages. Linking should add value. Value to the visitors from other sites that linked to you, and then value to them when you send them to another page on your site. If the links make sense – keep going! Internal linking is great on-page SEO practice when done well.