Hi @6640570 Welcome to the community, yes you can log in to your router remotely although you need to make a note of your dynamic WAN ip address to do so. This can change without notice so it won't be something to be relied on.
You can have the same ip address for weeks or months all being well but something like a thunderstorm or a NBN network issue can force your router to drop it's ip and reconnect with a different one.
To enable remote management log into your router then navigate to advanced > system tools > administration > remote management,
tick : Remote Management: and Remote Management via HTTPS:click save and make a note of your WAN ip address that will be faintly displayed in the box under: Manage This Router via the Address:
You can then test it using a mobile device by typing HTTP://xxx.xxx.xxx.xxx (your wan ip) in the browser bar. once you see the log in page simply log in and navigate to the wireless tab and uncheck the boxes for the 2.4 and 5g networks click save and that's it.