The traffic is pretty terrible, and you'd easily lose your day to the back of a Toyota Avanza if you are too ambitious with your plans.
I'd consider going across to Sanur and getting a boat to Nusa penida, at this time of the year the East coast is generally better (cleaner). That would be a nice day out with perhaps only 2 hours in the car.
My hot take:
Uluwatu - nice temple and sunset views
Ubud - cultural tourist trap
Kuta - aussie party tourist trap (the worst of bali IMO)
Seminyak - fancy shopping tt
Nusa Dua - tt for tourists that prefer not to leave the hotel and private beach