A while ago I mentioned (in a video) how the upcoming SteamOS 3.5 for Steam Deck added in a colour vibrance setting, and now Valve seems to have expanded it even further with a screen colour temperature setting as well.
Here's a look at the difference between the default 7500K colour temperature and then turning it up to 11000K, with colour vibrance at default:
You can see the difference very clearly in the second picture where it's turned up, look at the difference in the blues.
This is currently available in the Main + Steam Deck Beta update channels, which you'll see if you turned on Developer Mode, and then select to see the Advanced Update Channels in the Developer menu in settings. I would firmly advise against this though, as it's updated often and can be full of big bugs (there's a reason it's hidden). Stick with the normal Steam Deck Stable / Beta.
SteamOS 3.5 is sounding quite exciting now, hopefully it's not too much longer until it's released.