Hello,
AnkiHub does not delete any flashcards you have in Anki. This Dorian deck is not an official deck maintained by the AnkiHub team, so I can’t know its exact content.
When you download a deck from AnkiHub, cards from another version of the same deck may get merged. It might feel like you lost some cards, but in reality, you didn’t.
Another thing that can happen is that after downloading a large deck, Anki will prompt you to sync with AnkiWeb. You will be given the option to upload to or download from AnkiWeb. If you choose download from AnkiWeb, you might overwrite your local Anki data with an older cloud backup that has fewer or no cards.
The solution now is to restore from a backup created before this happened to see if any of those files work and don’t trigger an error: How to Restore from Backup