Please charge the remote as advised by Apple: Charge the Siri Remote - Apple Support
- directly to a computer USB port,
- or to a power adapter in an AC socket.
Other USB ports may be less suitable for charging.
The charging time from nearly depleted to fully charged should be about 2.5–3 hours.
If the issue persists when doing everything as intended, then contact Apple Support.
The front of the remote has an IR diode. It doesn’t shine in a light frequency that your eye is sensitive for. It is not used as indicator that the remote is charging. It is used for volume control directly to the TV or audio system (unless you have an AV receiver that supports volume control over HDMI-CEC).