I agree that as a practical space HSL is limited. Indeed, HSL was supported in the first two versions of Photoshop, but was abandoned as being too inconsistent. A conversion to and from HSL resulted in a mess. However Photoshop, like all design apps, features an HSL colour picker.

Thanks for introducing me to OKLAB.

> From my perspective that hue is the independent variable to set first

Agreed.

> Color spaces definitely defy straightforward intuition about them.

You are aware of Kuehnis book "Color space and its divisions."? It is a great read on this fascinating subject.