EDIT: But, yes, if there's lots of dark matter not uniformly distributed in the universe, then that dark matter would have differing effects on time dilation in different parts of the universe. Questions: Do the great voids contain much dark matter? What about non-void areas that also have very little DM somehow?
Unlikely. DE and DM are very different problems, sharing only a word in their casual names: dark :)
The galaxy rotation problem requires either modified gravity (MOND, etc.), actual dark matter, finding that the measurements and/or their interpretation are wrong, or something else. There are some GR effects to consider, mainly frame dragging, but frame dragging doesn't seem to be anywhere near enough because the frame dragging effect diminishes with the same proportion as gravity: inverse square distance.