Go to dashboard page of the router > Advanced > Maintanence Diagnosis > Configuration File management.
and download the configuration file, open it in the text editor, and edit tag AclServices and optionally X_HW_CLITelnetAccess.
And re-upload the modified configuration file and wait until it fully reloaded, your Internet connection might be temporarily down in that moment.
If everything okay, you should be able to access the SSH or Telnet services on your router with default credential.
default credential for SSH or telnet: username: Eproot password: adminEp
ssh -oHostKeyAlgorithms=+ssh-rsa Eproot@192.168.18.1
To list available commands, just type ?, the question mark also useful if you put it as postfix on each command.
It also support tab as autocompletion, however you can't delete character you've type with backspace, IDK why it's designed that way.
Even though there's su command, it's unfortunate I can't get full root access with regular shell.
You might want to change default password after enabling the SSH service:
WAP>set userpasswd Eproot