DIAGNOSIS The remote isn't bad. The issue is almost always interference from other IR/Bluetooth sources (like soundbars, LED lights, or even sunlight) or weak batteries confusing the gyroscopic pointer sensor.
FIX Replace the remote's batteries with fresh, high-quality alkaline batteries. Do not use rechargeables as their lower voltage (1.2V vs 1.5V) can cause performance issues. Then, re-pair the remote: point it at the TV, press and hold the Back and Home buttons together for 5 seconds until the pairing prompt appears on screen.
IF THAT DIDN'T WORK There's likely strong infrared interference. Make sure the TV's IR sensor on the bottom bezel isn't blocked. Turn off or move any other devices that use IR remotes (like a cable box) that are directly in front of the TV. Also, try using the remote in a dimmer room, as direct bright sunlight can flood the sensor.
HEADS UP You can also use the remote as a standard button remote without the pointer. Just press the Scroll Wheel in the center to toggle pointer mode on/off. If the pointer is off, navigation uses the directional pad, which is often faster for menu diving.