if i change the video quality to best, in the discovery plus app on sky q, is it free to watch the tnt sports in high quality

As of my last update, the viewing options for content on Discovery+, including the ability to watch channels like TNT Sports, can depend on your subscription package and the agreements between service providers. Changing the video quality to "best" generally means you're selecting the highest available quality, but it doesn't necessarily affect whether you have to pay for content that requires a separate subscription. If TNT Sports is included in your subscription through Sky Q and you have access to it via the Discovery+ app, then you should be able to watch it in high quality at no additional charge. However, if TNT Sports is a premium channel that requires a separate subscription, you would still need to pay for that access regardless of the video quality setting. For the most accurate and up-to-date information, I recommend checking your specific subscription details on Sky Q or contacting customer support for Discovery+ or Sky.