Beryl router (GL-MT1300) LAN ports are unusable while it is connected to 5G?

Hi everyone,

Short and sweet question: if a router is connected to my phone for the internet, can I use its LAN ports to connect to other devices such as managed switch?

Longer Description

Ok Im using Beryl for a very specific reason: using 4/5G and then use its LAN portsfor other devices. For that I get this setting when I connect the router to the phone:

IP Address 172.20.10.7
Netmask 255.255.255.240
Gateway 172.20.10.1
DNS Server 172.20.10.1

Now I want to extend this network by adding a managed switch (plug & play). However in the UI it shows 0 Lan clients. My setup as following, any help on how to setup/debug is appreciated, thanks.

Phone (4/5G) <=> Router <=> Managed Switch <=> 5 other machines

This should definitely works without problem.

Can you try another lan port on Beryl to make sure if it the lan port is defective?

I am using this set up in my office.