Roses are violet, black is grey, why are there no colorspace options? (and to all a good day!)

I’ve just installed CoreELEC (S905W) on my X96 Mini and I immediately noticed the colors are off.
To test this I have 2 identical monitors side by side, one connected to my PC and the other to my X96.
The X96 seems to have a higher contrast, making the darkest blacks considerably greyer and making bright reds a bit purple.

Reading some old threads on here it seems like there was a colorspace option in the Settings->CoreELEC screen which have since been removed.
All of my displays are pretty old and require RGB 8 bit inputs.
How can I fix this?

Add "echo 'rgb,8bit' > /sys/class/amhdmitx/amhdmitx0/attr" in and reboot

Thanks, I’ll give that a go.