GoKawiilHDMI eARC, or HDMI Enhanced Audio Return Channel, is an even more capable version of HDMI ARC that was introduced with the HDMI 2.1b specification in 2023. HDMI eARC has begun to replace HDMI ARC on some newer TVs because of the expanded number of audio formats it supports. In comparison to ARC audio, which is bandwidth-limited and in many cases still sends compressed audio to your speakers, eARC has the bandwidth to handle completely uncompressed, lossless audio, even when dealing with complex multi-speaker standards.
The HDMI Forum says that HDMI eARC "supports the latest high-bitrate audio formats up to 192kHz, 24-bit, and uncompressed 5.1 and 7.1, and 32-channel uncompressed audio," along with branded audio formats like DTS:X, Dolby Atmos and Dolby TrueHD. It's plainly better, though using HDMI eARC does mean making sure you have a high-speed, properly rated HDMI cable to reap all of the benefits.