Secondly, HDMI Alt Mode only supports the older HDMI 1.4b standard, rather than HDMI 2.0b. That means 4K (UHD) video will work, but only at 30FPS, making it essentially useless for gamers or ...

In case you're unfamiliar with this particular accessory, it has a male USB Type-C connector on one end and a female HDMI port on the other, and it's supposed to mirror devices' screens onto TVs ...

The Sabrent USB Type-C to Dual HDMI and DisplayPort Adapter works with all Windows 10+ and macOS 10.6+ devices with a capable port, though only mirror mode is supported on macOS.

A USB Type-C to Type-C cable is included for your convenience. Display Everything. You can add up to three displays with just one USB Type-C port. Supports 4K HDR and HDCP 2.2. DP1.4/DP++ & HDMI 2.0b.

USB-C, which has become something of a "do-everything" connector standard, has added an alternate mode that eliminates the need for an adapter when connecting to HDMI displays.