I would like this too! If you're on iPhone, you can use the "select text" feature, highlight all the text and then translate it. Definitely would be easier to have a button/menu option
Not as efficient, but you can have Google Assistant translate any text on screen if you pull it up and hit the translate button. Drawback is just that you can't interact with the page while Google Assistant is translating it.
The most extensive catalog of the world’s languages, generally taken to be as authoritative as any, is that of Ethnologue (published by SIL International), whose detailed classified list as of 2009 included 6,909 distinct languages.