So apparently I was not going insane and we really use to have more screen modes than the vivid and natural that we have now. In fact there are 5 of those. Each one targets a different color space and is assigned a specific ID:
Fun fact, DCI P3 is the color space that the iPhone targets.
To be able to access the other color modes, you need to know how to use ADB and have it set up in your PC already. Connect your phone to your PC, and in command prompt type
adb shell settings put system screen_mode_setting {ID}
where you change {ID} with one of the five numbers from the list above. After you do so, go back to Settings > Display > Screen Mode and then just go back to apply the new mode.
Personally I went with Amoled Cinema, but please discuss in the comments which mode you liked better. 😊
A pro tip is that you can do it without needing a pc or adb. On playstore downalod an app called SetEdit and edit the setting with the corresponding number. Than, as you said, go into screen mode option and back and you've got your hidden mode applied.
