Unicast streams like Netflix, Youtube etc, are not a very efficient way of distributing content to multiple users, but they do provide the content providers with a lot of useful information about how people are using their services, and how to target advertising
BT YouView distribute their extra subscribed channels like BT Sport, using Multicast, which does not have any impact on the upload path, apart from a very tiny amount of information which is sent back as part of the YouView platform.
I can see issues for gamers getting worse, not better, as more unicast content is consumed.
How do I get that
By paying for an extra phone and broadband package to be delivered over a separate pair of wires, an expensive option, assuming there is capacity on the local copper network and fibre cabinet.
Trying to make better use if your existing connection, is a much cheaper option, but you need to have a good understanding of networks and routers.
This is only a customer to customer help forum, and we are all just customers.
If BT have said that there are no faults on your broadband service, and you are getting the correct upload and download speed, then the problem is being caused by your network configuration.
Latency will normally increase, the more users you have connected to your broadband. Its up to the account holder, to restrict the number of users that connect to the line they are paying for.
If you are sharing a connection with other unrelated people, then perhaps it may be an idea to suggest that they get their own connection?
Latency is not directly related to connection speed. You can have a slow connection (10Mbs) and very low latency, and a fast connection (80Mbs) with very high latency.
There are many factors that determine latency, its just a case of identifying the cause.