Any thoughts on what color space you'd prefer to use? I'm working on a Tailwind palette creator (https://www.inclusivecolors.com/, it's based around letting you visualise the curves you mentioned), which uses HSLuv right now to avoid problem 2 in your list. HSLuv has perceptual uniformity as well (which is great at helping you pick colors that contrast) but it doesn't support P3 unfortunately, similar to Google's HCT color space.
I'm not seeing much demand for P3 at the moment though. Most designers I've spoke to don't know it exists.
I'm not seeing much demand for P3 at the moment though. Most designers I've spoke to don't know it exists.