The right controller is often used 10x as much as the left controller, mainly because most people are right handed therefore game/app devs etc accomadate this by putting most of the action on the right controller, hence why is runs down quicker.
You need to give some time context as what you mean by "really fast", is after 1 hour, 1 day ...?
The other thing to check for is controller drift. I noticed some time ago that my stick on my quest controller started to always drift to the right even though I wasnt touching it, this is en effect constanty transmitting, therefore battery consumption was quicker than normal.
And dont use cheap batteries from Amazon, these are useless. Get some decent rechargables or Duracell. If you are in the UK, find Asda batteries are just as good as Duracell.
