Hello, friend!
The differences between the EG8141A5 Datasheet and the GUI provided by you are as follows:
As described in the EG8141A5 Datasheet:

EG8141A5 does not support 5 GHz Wi-Fi.
On the Wi-Fi Coverage Management page of the device WebUI, configure 5G Parameters for APs that support 5G Wi-Fi.
To configure 2.4 GHz Wi-Fi, perform the following steps:
Click the Advanced > WLAN tab, and choose 2.4G Basic Network Settings from the navigation tree on the left. In the right pane, configure the basic parameters of the Wi-Fi network.
Note that you need to use the web interface of the administrator account to perform configuration operations.
Thanks!