Sorry but they're telling you porkies. The VR600 100% supports DHCP Option 60/61 on Sky adsl/fttc lines (at least). The support agent clearly hasn't got the foggiest idea, you might as well have asked your cat (or any cat on the street)
Is there a comprehensive list of new and old modem routers that are set up to work with Sky and Now broadband fibre to cabinet service?
community.tp-link.com
However..............for Sky FTTP lines it seems any TP Link modem/router loses its Sky MER DHCP Option 60/61 setting once you put in in router mode only (ie switch off the modem)
Hiya I'm after some help and guidance to enable me to use a TP Link VR2800 on my new Sky Ultrafast Plus package. The new Sky Hub is good but the signal strength in the far to reach places, including my office / garage isn't great, so I bought the abo
community.tp-link.com
If you have already bought the TP Link VR600 and it can't be returned, then the only way you can use it is to connect it to the Sky router, as an access point. Otherwise buy something like the Asus RT-AX86U which will easily work on Sky FTTP (you might need to install Merlin firmware on it)