Applying a color tint didn't destroy color accuracy for me. Did you actually try to match up your screen to a known good screen when adjusting color tint? And did you set the intensity to the lowest setting?
I purchased an i1Display Pro Plus and ran some tests to measure the effect of applying the color tint I posted earlier in the thread, and here are my results:
Default, no color tint applied, Night Mode off:
- Max brightness: 825.1 cd/m²
- Color temp: 6521K
- Average ΔE: 0.99
- Max ΔE: 2.03
Color tint applied, Night Mode off:
- Max brightness: 669.7 cd/m²
- Color temp: 8203K
- Average ΔE: 1.17
- Max ΔE: 3.21
Color tint applied, Night Mode on:
- Max brightness: 630.8 cd/m²
- Color temp: 6633K
- Average ΔE: 1.26
- Max ΔE: 3.7
As you can see, applying color tint and Night Mode did reduce max brightness quite a bit, but the 12 Pros have such high brightness to begin with that it's not a huge deal. It essentially reduced the brightness to the same as the regular iPhone 12, which have a max brightness of 625 cd/m². Although if you have a regular 12 or 12 Mini, the brightness might be reduced too much.
As for the color accuracy, it was reduced, but it's still very good even with the color tint and night mode applied. This will obviously depend on how you set the color tint slider. If you just blindly set it to something that you think looks good, it might make color accuracy a lot worse. I would recommend trying to match it to a phone or computer with a known good display.
Finally, we can see that it really is necessary to turn on Night Mode to a low setting if you apply a blueish color tint. With just the color tint alone and no Night Mode, the color temp was way too cool at 8203K. But with Night Mode, you could essentially bring it down to whatever you want.