Begin with a baseline
Play the same source on the same device at your normal viewing time. Note the picture quality and how often interruptions occur. Pause large downloads on your own network and compare again. A speed-test peak alone does not describe stability throughout an evening.
Compare cable and Wi-Fi
Where your device supports it, compare Ethernet with the usual Wi-Fi connection. Keep the player and source unchanged. Walls, distance and other devices can affect wireless performance. Do not assume a new subscription will fix a weak connection to the television.
Change quality deliberately
Try a lower available resolution and record whether stability improves. Higher-resolution sources require compatible decoding as well as sufficient sustained network capacity. Selected 8K content is not an appropriate default for every television or connection.
Share the test results
Report whether the issue affects one feed or many, the device model and the result of the wired comparison. Support can help examine available server options or player settings. A VPN is not automatically faster; use it only as advised for your supported setup.