Supposedly okLCH is better as its lightness is based on perceived lightness by human eyes, so for example 50% bright yellow appears same brightness as 50% bright blue.
In okLCH it's very easy to make invalid values, for most colors the valid brightness range is from 40% to 60%, so stay in there to see the difference, I guess ¯\_(ツ)_/¯ (all colors here are at 50% HSL contrast and oklch.com was used to convert)