The Division 2 Steam edition just got a patch stating:
Fixed an issue that caused the game to be unable to boot on Steam Deck
We can confirm (as shown above) that we can now run the game and enter the game correctly on the Default Proton.
Full The Division 2 Steam Deck Gameplay and Best settings videos will be available soon.
UPDATE: Best Settings and gameplay for the Division 2 has been added here: https://www.steamdeckgaming.net/best-settings/the-division-2-steam-version---best-settings