Diagnosis
It's normal for the One Connect box to get warm, but "super hot"—where you can't keep your hand on it—often means it's starved for air. Mounting it flat against drywall or stuffing it in a media cabinet is the usual culprit.
How to Fix It
You need to give it at least an inch of clear space on all sides, especially the top and bottom. If it's mounted behind the TV, use the included spacer or get some velcro strips to create an air gap. Make sure the vents aren't blocked by cables. Feel it again after 30 minutes of watching; it should be warm, not scorching.
If That Didn't Work
Check what's plugged in. High-power USB devices (like external hard drives) or an overpowered soundbar via HDMI can draw more current and heat it up. Try unplugging non-essential peripherals to see if the temperature drops.
Heads Up
Chronic overheating can lead to premature failure or the TV randomly shutting off to protect itself. If it's still too hot with good airflow and nothing extra plugged in, contact Samsung. There's a small chance the unit's power regulation is faulty.