Looking at the
Wikipedia:WikiProject Languages/List of ISO 639-3 language codes (2019) shows multiple entries for Yupik with Central Alaskan Yupik (esu) as an example.
Heading off to
ISO 639 Code Tables and enter yupik in the Language Name(s) containing search box comes with with the same 5 entries for Yupik languages. esu is likely the one of those that you want (Central Alaskan Yupik).
Searching for Dena'Ina shows no entries. A quick Google search on 'Dena'Ina language' shows it is also known as Tanaina. Entering tanaina in the seach box comes up with tfn as the ISO 639-3 code.
Neither of those choices show in the calibre language listing.
Google can be your best friend.