TCL 65QLED870 HDMI 2.1 Signal Dropping Out

Hey,

I've bought this new TCL TV, the 65QLED870. Everything has been fine so far, except that I randomly lose the HDMI signal. As far as I could test, it only happens when using HDMI 2.0/2.1, when running 1080p@240Hz or 2160p@60/120Hz. I tried four different HDMI 2.1 certified cables, and three different devices. That's what lead me to think the problem is with the TV.

The TV's OS is up to date and I tried to do a power-cycle (unplugging it, holding the power button for 30 seconds then waiting two minutes before plugging it back in). I also tried a factory reset and to not touching any settings (apart from the game master settings) before testing.

I tried two ports on the TV, the 4K@144Hz and 4K@120Hz ones.

Sometimes I don't lose signals for dozens of minutes at a time, and sometimes it happens 2-3 times in a minute. Sometimes it cuts off for one second then come back, sometimes I have to fight to get a signal back (unplugging and re-plugging the HDMI cable, restarting the TV...)

Is there any hope that there might be another thing I could try that would prevent me from having to RMA it?