My iPhone XR is at 82% maximum capacity, do I need a new battery?

Battery health degraded --> Source: iPhone battery and performance - Apple Support (IN)

If battery health has degraded significantly, the below message will also appear:

Your battery’s health is significantly degraded. An Apple Authorised Service Provider can replace the battery to restore full performance and capacity. More about service options…

This message doesn't indicate a safety issue. You can still use your battery. However, you might experience more noticeable battery and performance issues. A new replacement battery will improve your experience. More about service options.

No, only if it drops below 80% you're eligible for a replacement

You probably have a few more months before the Max Capacity drops to under 80%. That would be the time to replace the battery.