I don't know, I guess one could always imagine a slightly more complex, slightly more sophisticated, slightly better algorithm than the ones available.
I think one problem is that human color perception isn't mathematically clean, we have (for instance) a bias toward perceiving colors differently on an anatomical level. And then you've got cultural connotations of colors, at different levels of granularity, right down to personal preferences. Insert shrug emoji here.
I can say I've never found one yet that I wouldn't trust without supervision.
My favorite is Huemint, it's very slick, but it's still not there.
https://huemint.com/
