DLCs worth playing of all 3 games (DLC names and order)

I would suggest Origins, DA2, DAI with Jaws of Hakkon BEFORE the final mission, the Trespasser after. JoH does give you more insight into the first Inquisition and into the religions of Thedas and, how it was closer to the time of Andraste. Quite interesting.

Decent is good too, if you want to learn more about dwarves and Lyrium and, can be played any time form level 15 on, though I suggest level 17 to 20 to complete that DLC.