>>39303930??? for sure can, Dyna water gives rain and dyna flying gives speed.
Lets take gyarados for an example.
Turn 1: DD
Turn 2: Dynamax and use Dyna water you are now +1 with rain with (potentially boosted stats) using 140 base power moves.
Turn 3 you can click dyna bounce with one turn activation and get to +2 speed so you can not be revenged.
Now you still have one more dynamax turn with insane buffs and if you already killed something you are going on a moxie sweep.