If you disable the Color Rendering tool, PhotoLab still uses the “Camera Default Rendering” profile (with no protection of saturated colours) in order to assign appropriate colour values to the demosaiced pixels in the Adobe RGB working space, before converting them to the monitor profile and showing the preview to the user.
“Camera Default Rendering” is equivalent to what in Adobe world is called Camera Standard profile – it’s DxO’s emulation of the look designed by the camera maker for the specific camera model. As such, it’s not the “colour as captured by the camera’s sensor” but it’s interpretation of an interpretation, if you know what I mean.
Although PhotoLab’s default camera profile is the “Camera Default Rendering”, their baseline profile seems to be the “Neutral color, neutral tonality” one. The rendering profiles (e.g. DxO FilmPack camera emulations, or ICC/DCP camera profiles) seem to be put on top of the “Neutral color, neutral tonality” input profile – that’s at least how I understand the Intensity slider under the Rendering box – that Intensity slider acts like a layer opacity slider in Photoshop. And the “Protect saturated colors” Intensity slider probably works on a formula similar to the one used by the Vibrancy slider (a channel mask). It’s necessary because the profile-embedded tone curve might cause oversaturation if the profile doesn’t employ gamut compression.
Incidentally it’s possible that OXiDant’s Huelight profiles were designed without that gamut compression, that’s why they clip so easily in PhotoLab.
One last thing, the “neural tonality” profile name is a bit misleading because it suggests we get a linear, scene-referred rendition (“as camera saw it”). But the profile is gamma encoded, i.e. there is a midtones curve, but it’s neutral in the sense that there’s no shadows dip in the curve.