Personally, no. DR was still extremely early in its story when the game was taken offline: only 3 episodes had been released, and they were still worldbuilding and establishing the setting and characters. We have no idea how many episodes they had remaining, and thus no way of accurately predicting how long it should take them to finish all of that work. Even when the game was on a regular schedule and alternating with UX, it seemed like they were struggling to get story updates out on time. IMO their original release schedule vastly underestimated the amount of work they had left to do and led everyone to set the wrong expectations.
While the tweet does say the further delay was caused by major additions to the scenario. I don't think those would have necessarily come from Phase 2/other titles (although it is certainly possible!), but rather that stories can evolve unpredictably as they are being written and the team may have simply decided to expand DR's scope.
Anyways, I'll take this time to remind everyone again that there's only 2 cutscene animators working on this game and of the impact the pandemic has had on game development, you know the drill, yadda yadda.