As someone else suggested you could try to head into Kuta. Traffic can be really bad, but, if you haven't been before and you think you can swing it with the time, I would rec just grabbing a bintang (if you drink), check out the beach (hopefully there will be some surfing going on), and check out a couple streets in town.

If you can push your garuda flight back to give you some more time, I would def suggest checking it out. (I always enjoy getting to see even just a few hours of a new place when I get the chance)