You need to explore the suggestions I’ve made if you wish to try and see if you can improve on your connection. to be honest and frank on the BT router there’s very little control of the network and again i point you to PingPlotter so you can watch what’s going on and to look into other routers including the modem if you wish to pursue a better gaming experience. BT routers are simple, they do their job but think of your network usage and how that effects your traffic within the network. There are routers out there that will offer far better control and again I’ll be honest but base ping is only a snippet of your network performance and only when you start to look at how your traffic within your network is handled will you start to realise that even a 6ms ping means nothing if your internal network has no control of its traffic while you game away.
Add in to that you don’t have any say on the server you connect too for the majority of games then you start to see why others that like gaming start to look into routers that offer far more control and a few even have the ability to connect to the lowest pinged server.
If however that’s not an option then a base ping of 25 is not a disaster, I bet when there’s traffic on your network that spikes well above 100ms plus. Perhaps that’s where your issue is if you are experiencing issues and that’s where some of the better QoS systems like Cake, fq CoDel, Netdumas take of CoDel and so on come into play. Like I say run PingPlotter and watch how your connection responds, you may find it’s the routers inability to control traffic that is causing your issues.