Fix the room before the gear
Move bright lamps away from the screen, reduce reflections and place the display close to eye level. Those changes cost nothing and can make a bigger difference than another accessory.
Give streaming traffic a cleaner path
If possible, use Ethernet for the main TV. Otherwise place the router in the open and avoid hiding it behind a television or inside a cabinet. A stable signal helps live video more than chasing a higher theoretical speed.
Use sensible picture settings
Many displays ship with extreme sharpening and motion smoothing. A neutral or cinema-style preset is often a better starting point for films and sports, then you can adjust brightness for the room.