The mobile network around Goodison is poor, certainly for data. The reciever can only hand off a limited number of connections as even the 5g network is essentially just 4g+. The receiver modules are still limited in input connections, but the output speed has been increased giving the feel of faster speeds.
True 5g networks uses reciever modules that can handle in excess of 5k concurrent connections using Maximum Input Maximum Output (MIMO) technology. That's more than 5x the current connections. BMD will have a network of recievers within the stadium linked up to a hardwired backhaul, hooking directly into the cities high speed fibre ring main. There is also Vodafones 5g mast within distance towards the Costco. This will be the first football stadium in the world to incorporate this technology to this scale.