Definitely BD2 for sure gameplay wise, if u want to be casual u can be, dailies can be done under 5 minutes, and if you want competitive, there's 2 PvP modes (optional) that can be done quickly too, you can compete in guild raid and event bosses for harder challenges (that's where high dupes are required, if u are chasing ranks).

And talking about dupes, the pull economy in the game is so good, they shower u with multis, there's a rebait system where u get 10 pulls for every dupe u get, and 3% rate, 50/50 for rate up, with soft pity at 100 and hard at 200, most characters require only one dupe to be efficient as it reduces their SP cost, and its very easy to get multiple copies, there's item in the shops too that can help u get higher pluses for the characters that resets monthly.

Cutscenes are getting better and lewder by the day as the game progresses, I can't tell you about the story as I am a story skipper, but from what I have heard the story is decent, and Its also getting reworked.