It may be that brandyman is suggesting OP try a specific ASUS router, although from what I can see here the one mentioned does not contain any modem, either ADSL or VDSL. My intervention was based on looking at the Netgear web site here which clearly shows that the OP's new router will work with fibre but only when an external VDSL modem is

How to Use Your Own Router with AT&T U-verse The built-in router AT&T supplies is only 802.11 N 2.4 GHz. If you plan on streaming HD videos from a local file server or transferring large files via Wi-Fi then you will want to use your own router with the latest and fastest 802.11 ac Wi-Fi. Reuse an old router to bridge devices to your wireless Check the DD-WRT router database to see if your router is supported. If your router isn't supported, …

Yes you can use your own router - if it has option

Any router that DD-WRT can be installed on can be turned into a wireless repeater and bridge. A wireless repeater takes the signals from your main wireless network repeats them on another.

Use an Old WiFi Router as Repeater, Wifi Extender, Access

Jan 30, 2020 Can you use any wireless router with any broadband