Oh the jump in vividness from the S22U to the S24U will be huge! I have all three sitting right in front of me! The S23U in vivid mode with the red, blue, and green sliders set all the way down was perfect to me. I don't like too much over saturation but I also don't like a color display that looks like a CRT with the capacitors in their way out either.
These phone displays should have the same color adjustments as TVs IMO. I use a LG Oled TV and the color and contrast on it is perfection, but after painstaking adjustments. I've always hated getting a new display because they never look rigjt to me out if the box.