OKLCH isn’t perfect either
I’m kidding, OKLCH is awesome. But the human brain works in mysterious ways, and one of them is the Helmholtz–Kohlrausch effect: saturated colours appear brighter than less saturated ones. OKLCH’s lightness doesn’t account for this, so a palette with equal L can still look uneven when its chroma varies.
Look at the colors above, which looks brightest to you?