I wanted to use the AX58U as I need to split the wifi for 2.4g devices as well as using the USB3 port as a SMB share..
I was happy to remove the phone line as I have mobiles and nobody knew my landline number anyway.
Once the SKY MAX router had shown that the new fibre connection was working correctly and at speed, I removed it and installed the AX58U in its place.
This following part is important.
I had not powered the ASUS on before, so it's maiden boot was with the cable plugged in connecting WAN port to working ONT .
I was also directly connected via wired ethernet to my laptop for control.
On booting the laptop connected and I got to the admin pages, where it asked me to create wifi networks (single or dual) and also create the admin user and password for the router.
The AX58U connected to the ONT without any issues and without any questions.
It informed me it needed a firmware update, so the WAN was working fine.
Strangely, it had decided to setup the standard network as 192.168.50.x which was a bit weird.
Changing the routers address to 192.168.1.1 also prompted it to automatically change the DHCP range at the same time.
(you can't do both at the same time..manually)
I could then configure the DHCP for static ranges and the unit was working perfectly.
All in all, the AX58U was essentially plug and play, without any passwords or settings needing to be changed to connect to the ONT and produce a stable connection (slightly faster than the MAX box.)
Hope this helps if you are needing to change routers for your use case, as I havent seen much actual detail on this particular inexpensive and feature rich device.
