<p>The BT Sport app closed on 12th October and has been replaced by discovery+. <a href="https://community.bt.com/t5/TNT-Sports-on-TV-Online-player/The-BT-Sport-app-is-closing-on-12th-October/td-p/2312034">Find out more about activating TNT Sports on the discovery+ app</a>.
I was experiencing really bad latency/lag too. I'm currently using wtfast on my pc and so far its really helped improve online gaming. if your internet is fine, speeds are fine then its probably the route your data is taking to the game servers. Using wtfast or any good gaming vpn can be worth a shot, although results do vary. Most offer a free trial period so you can try one out and see if it works or not