Perhaps a little bit of explanation about the FTTP supply might be helpful. The roll-out of FTTP is an ongoing process and even at the end of the roll-out there will still be some properties not connected to fibre. The government have defined a USO (Universal Service Obligation) -
https://commonslibrary.parliament.uk/research-briefings/cbp-8146/ - which stipulates 10Mbps download and 1Mbps upload as the minimum acceptable connection at a cost of £45 per month or less. The USO can be discharged by any means so that a mobile telephone signal or Starlink-type connection would be as acceptable as a ground based service. If the area is not in the BT plan but an altnet supplier serves the area that then discharges the USO. There is an excess charge get-out clause but for most people currently tied to things like a 4Mbps download then a faster connection in some form will be coming in the not too distant future.
In regard to BT connections (which includes all of the ISPs who buy capacity at wholesale from BT) the FTTP supply has no relation to the existing telephone exchange map. There are fewer nodes for the FTTP system than there are for the old telephone-line connections with the fibre being supplied from head-end exchanges covering the area of a number of smaller, subordinate exchanges. Where premises are supplied with FTTC through their existing phone line (sold by the ISPs with the weasel-word "fibre") then the fibre from the head-end exchange is already in existence and runs to the cabinet supplying the property. The additional work required is to run fibre in parallel to the copper wire from the existing cabinet site to each of the premises served. Altnets each have there own system with their own fibres installed from a node where the altnet has access to the internet spine through switches and splitters to each of the premises they serve running alongside any BT installation. The farcical result of that is that in the areas where there is competition an ONT (Optic Network Termination) - the equivalent of the telephone master socket - needs to be supplied to each of the premises for each of the networks when that service is installed. These are the demarcation point of the network and are the property of the network so cannot be removed unilaterally by the premises owner. People switching networks and suppliers could end up with two or three ONTs on their internal wall.
In summary, even people who are a long way from any exchange and suffering low speeds have a right to be connected with a guarantee of 10Mbps download and 1Mbps upload. If there are no published plans to achieve that connection they should use the USO process to start things moving.