Good day, I had the same intention and contacted Init7 ->
"You can use the ASUS router, this must then simply be combined with a
TP-Link converter, as the ASUS does not have a direct fibre input.
fibre input.
The router must then be set to "automatically DHCP", there is
everything."
However, you have to buy an additional cable. You can also do this here at Digitec (
https://bit.ly/31EFYRh), but it is relatively expensive.
I previously used a Fritzbox 5490 + repeater combo. I only switched to Asus because of VPN, which I need for work. If you don't need VPN, I would recommend the above combination, as measurements have shown that it is much faster than with Asus.
I sell my old devices here, if you are interested:
https://bit.ly/2Stnj6G
Kind regards