But when connecting ATEN UC-4854, it was not detected.

Asus Tinker OS is based on a tailored Debian Linux which many drivers/features are omitted in order to achieve lightweight.  

UC4854 does not need a driver for Ubuntu18.04, Debian 8 and latest Debian 9.

If you are using Asus Tiker OS, user DIY tuning are needed.

Please try to replace the original zImage which is located at /boot with the attached file. And reboot for testing.

$ sudo  cp  zImage  /boot