The table on the "Exploration of Jupiter" Wikipedia page suggests Dragonfly will be the first mission to the outer planets that will not use a gravity assist from Jupiter. Is there a source confirming this?
Here is a paper which among other things includes the results of a trajectory search. They say
Gravity assists of Earth, Venus, and Mars were included with a patched conics assumption. Jupiter was immediately discarded as it is out of phase during the desired time period.
The trajectories proposed in that paper involve multiple Earth and Venus flybys. I guess if the mission was delayed a few years then Jupiter might come back into play.