I just bought a TP-Link VDSL2 modem/router/wireless AP for a mate to replace his failing one and it's pure junk. It actually forces you to download an app and sign up for an account just to configure it. No settings in the web GUI at all (although it actually has a HTTP server and web interface for stats). It literally took me an hour to set up because of that garbage. The app kept throwing me out and I'd have to factory reset and start all over again, for no reason at all. Shit like this seems to be a common theme, not just with TP-Link.
Why was an individual buying a VDSL2 modem? They are normally supplied by the ISP. ISPs are the market for these products, The suppliers do what the ISPs want. The ISPs want remote management.
In Australia, you can get a modem/router from your ISP (usually for free) if you choose to, but you can also BYO equipment. You can walk into any office supply store or technology store and buy them off the shelf, without any ISP branding or custom firmware. Quite often the ones the ISP supplies are extremely basic. Just enough to get you an internet connection, some kind of Wifi and VoIP. We don't lock our connections down to use specific modems or lock customers out of theirs (even if it was supplied by the ISP).
His router that was supplied years ago by his ISP was very old and was starting to fail. The Wifi became extremely unreliable and after a few clients connected, it became unstable. It was time for an upgrade.
Personally, I use a Netgate appliance running pfSense. From the street, the fibre goes into an NTD which converts it over to copper ethernet, then from there straight into the WAN port of my router for me to do whatever I want with. All the authentication/DHCP etc... is done on my own equipment.