Yes, you can find all that on Koh Chang, but perhaps not all at the same location.
WhiteSands is the main place for nightlife and is very busy during the day too - beach area quite crowded. It isn't my idea of a quiet beach or a relaxing place to be.

Quieter beaches (several) are away from White Sands.
We stayed at a place called Sea View Resort - I think it's on Kai Bae Beach.... very nice,right on the beach which really is almost a private beach.... except for some nearby bungalows, this is the only hotel on this stretch.
The hotel has a beach bar right on the sand - nice for drinks and snacks and you can sit inside or out.

It's a bit of a trip into White Sands area for ATMs, currency exchange, a bit of shopping or more nightlife - perhaps 15 minutes by tuktuk, but is very peaceful at Sea View.

It's set on a hillside so you go down to the hotel and then to the beach.... a bit of a climb up from the beach to your room or the restaurant. Walking up to the main road is a test of fitness but you can walk along the beach and then cut through to the road - a nice flat walk and some other restaurants along the beach too.

If you book Sea View, the bungalows are cute but pretty basic. The hotel rooms are a better bet and the new ones are very nice.

The only real criticism we have of Sea View is that the hotel does nothing to stop guests (often groups of people) reserving sun lounges early in the morning and not using them till they're good and ready, but denying everyone else a spot........ a potential source of conflict.