I assume this is still up to date. Take a look at…
https://availability.samknows.com/broadband/exchange_search
Put your postcode in, and under the LLU operator presence bit it tells you who has actual kit in your exchange. If they haven’t, they’re just reselling the same service, so usually only differentiator then is cost and customer service. Cable is separate obviously.
We ended up sticking with BT, at the end of each contract they say they’ll revert back to standard price, but you click a ‘special deal’ link and you keep the discount.
We’re across the road from the exchange, so a short bit of copper in, then fibre so get 70Mbps from standard BT ADSL.
In the house, I’ve had great results with a TP-Link Deco mesh setup. If your house is old and walls solid, you’ll still need a few units to get everywhere – we ended up with 4 to cover an old stone cottage and down to the workshops out the back. Been in a few years now, been faultless.