Apple 4K volume control not working anymore

Yesterday morning the volume control of my 4K Apple TV remote randomly stopped working. It was working fine the day before, never had any issues whatsoever.

After browsing the internet, I’ve tried everything:

• Unpaired and re-paired the remote by holding TV button and volume down
• Re-paired by holding "back" and volume up
• Charged the remote for hours
• Went into settings and turned volume control to Off, then back to Auto
• Unplugged HDMI cable
• Disconnected the power going into the Apple TV box
• Even did a full factory reset

At some random intervals, it will start working for about 20 seconds, but then it stops again. I’d say this happens every hour or so.

The Apple TV or remote isn’t broken as far as I'm aware, and I’ve had it for about 6 months. Whenever I press volume up or down, the LED on the front of the box does show, there is just nothing that happens. I also cannot control the volume via the Apple TV remote on my phone.

I have a Samsung 4K television, no soundbar, CEC is enabled, and the HDMI cable is almost brand new.

Could this be due to the latest software update? I'm all out of ideas what to try next.