Diagnosis
The system is likely bogged down by background processes and cached data from initial setup and updates.
How to Fix It
Force a full restart of the TV's operating system. Hold down the power button on the remote (not the TV) until a menu appears, then select 'Restart'. Do not just put it to sleep with a quick press. This clears temporary memory caches.
If That Didn't Work
The internal storage might be nearly full from app data. Go to Settings > Device Preferences > Storage. Clear the cache for individual apps (like Netflix, YouTube) and uninstall any apps you don't use to free up space.
Heads Up
Avoid using the built-in 'Developer options' to aggressively limit background processes—it can break app functionality. The TV's performance is generally snappy after a restart and some storage management.