At least as far as single player DLC is concerned. BioWare has confirmed via their official site that "there are no planned future patches for single-player or in-game story content" which basically means you have to rely onthe multiplayer APEX missions and various other media like books and comics to better flesh out the story.
On their official post, they said that they "decided to focus Mass Effect: Andromeda’s story on the Pathfinder, the exploration of the Andromeda galaxy, and the conflict with the Archon" presumably rather than relying on additional DLC expansions to add to the game. Now while the first Mass Effect had minimal DLC, after the release of Mass Effect 2 & 3 the concept of continuing the fight through DLC persisted... and with BioWare and in effect EA being the type who loves money... there is NO CHANCE that they didn't plan for DLC. Trust me when I say that they WANTED to expand on it with DLC and if their plans were to not include DLC all together... then why the hell did they take so long to FINALLY tell us?
While I did enjoy Mass Effect: Andromeda to an extent... it really was lacking. BioWare made a big mistake handing the reins of one of their biggest titles over to an ancillary team. Now I get it that they were working on Anthem, but geez... I myself and many of my friends were looking forward to ME:A and I know I'm not alone in being let down.
I really wanted them to get their shit together. I wanted this to be a good game and maybe I even gave it a better review because nostalgia is a powerful thing. But one thing is clear... unless BioWare can make amends, this is the end of Mass Effect.