Is the LG 43QNED84A6C good for gaming?

It is a 60 Hz panel without 120 Hz or variable refresh rate, so it suits casual console play but not fast competitive gaming. Input lag is fine for single-player titles.

Does it need a separate soundbar?

The set's built-in speakers handle everyday viewing, but a soundbar adds weight for films and sport. The TV has Bluetooth and HDMI for connecting one.

Yes. It uses a 200 x 200 mm VESA pattern, so a standard bracket of that size fits.

Does it have Freeview and satellite tuners?

It supports DVB-T2, DVB-C, DVB-S and DVB-S2, so it works with terrestrial, cable and satellite broadcasts.

Is 43 inches enough for a 4K set?

At typical sofa distance in a small room, 43 inches is comfortable and 4K detail is visible up close. In a large room, a bigger screen shows the resolution off better.

What is the difference between QNED and OLED?

QNED is an LED-backlit LCD with a quantum-dot layer; OLED has self-lit pixels with deeper blacks and wider viewing angles. This QNED set is brighter-friendly and cheaper to make at this size, but OLED wins on contrast.