@ken22 

There is no Wireguard seen on the tab section under VPN just like seen on the FAQ that you shared https://www.tp-link.com/us/support/faq/3559/

JUST TO CLARIFY MY CONCERN. My goals is to access the router's GUI (standalone setup-not Omada) from different/others locations. For that, so I can do modify, changing the configurations, backup and restore the router's config bin, etc.

NOTE: I will be using mobile phones(android) using Data Connection(cellular) to connect and access the router from anywhere. 

  @ken22 

Now i see that you are using older version of er605 which indeed does not have WireGuard. 

You could use openVPN then, it should provide similar results. Please use this guide:

https://www.tp-link.com/us/support/faq/3632/

Creating openVPN server on er605 would be more secure than adding 0.0.0.0/0 to your remote management settings.  Adding 0.0.0.0/0 essentially means you are opening access to your router for anyone on internet, and thats not the right way to manage your (remote) network securely.