[JPLeRouzic]

I wonder if it would be possible to install a 4G network extender [0] then implement IP route rules on the ADSL router, to forbid access to Facebook and co?

[0] https://www.verizon.com/support/4g-lte-network-extender-faqs...

[rosswilson]

Those extenders typically backhaul the traffic over a VPN back to the telco, so your router would never see the true destination (e.g. Facebook).