Traffic shaping is still QoS so I don't think it will help you I'm afraid.
So you are saying your connection isn't laggy itself but when others join with a bad connection and lag you are affected by the compensator is that right?
I have exactly the same problem. Contrary to BT's adverts, FTTC doesn't necessarily give you a better gaming experience. Certainly not on the consoles anyway. Choosing your own server without matchmaking and not playing in parties would help. Sadly not an option on COD, Battlefield etc.
I have a 9ms ping. When not hosting, it isn't a great experience to be honest. But as restarts says, when hosting, 90% of the time it is unplayable.

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Knowing how it works is completely different to understanding how it works.
Live BQM
FTTC - Aquiss Business 45
37.7Mbps Downstream
8.45Mbps Upstream
7ms Ping