I’m researching broadband providers as my BT contract is about to expire. When I joined BT I was given a smart hub 3, which I could not link to the Sonos. Eventually BT gave me an old hub, which has worked. We also tried to link a TPlink system to extend the signal. Our house is 3 floors with foil back plasterboard providing good insulation. 
Can anyone provide simple practical advice for someone who is not technically minded before I cancel our contract and then find another supplier is going to provide a router that is incompatible with the Sonos system? Current top contender would seem to be EE as they are now in partnership with BT.