If your MacBook Neo is producing a noticeable smoothing or softened appearance even though you have not intentionally enabled an effect.
macOS Tahoe does not provide a documented setting specifically called “Skin Smoothing,” “Beauty Filter,” or “Retouching” that you can turn off.
Apple’s documented camera controls cover features such as Portrait, Studio Light, Center Stage, Edge Light, Reactions, and Background, but none is identified as a skin-smoothing control.
Use video effects and mic modes during video calls on Mac
For a clean test, open a video application and click the Video menu in the macOS menu bar.
Make sure Portrait, Studio Light, Center Stage, Edge Light, Background, and Reactions are off.
Apple describes Portrait as background blurring and Studio Light as changing illumination, rather than as skin-retouching features. (Apple Support)
Apple also says that some applications may have their own camera-quality settings, so it is worth checking the settings within the particular service you use for your counselling sessions. (Apple Support)
If the smoothing remains across different applications with all documented video effects disabled, I would not claim that there is a hidden Tahoe setting or definitively identify the cause without further testing.
At this point, Apple simply does not document a user control for removing that particular appearance.
One practical workaround is to use an iPhone as the Mac's webcam through Continuity Camera.
This gives you a different camera source rather than the Neo's built-in camera. Apple officially supports Continuity Camera in macOS Tahoe. (Apple Support)
The important point is: you are not missing an Apple-documented “turn off skin smoothing” switch.
There currently is not one documented for macOS Tahoe.