I had a similar issue, although mine was a case of a break somewhere in the wiring within the building itself. Openreach were unable to source the break and a standalone line was not permissable.
Vodaphone came up brilliantly with a 4G/5G mobile hotspot
https://www.vodafone.co.uk/mobile-br...-wi-fi-hotspot
I have one now and it is so easy to use, no external connections required, just plug it into the mains and do the password etc on the pooter and away you go. Mine is actually significantly faster and cheaper than the fixed type broadband and with the added bonus that I can take it anywhere too.
Mine is the Max plan that gives unlimited data and no upfront cost for £23 per month (payable by DD or direct via Vodaphone website) there are 4 plans available via the link