It took quite some time for me to learn and understand more about color wheels, vector scopes and complementary colors. A big help with this are various very good Youtube videos of David Briggs. He does explain in the 30 minutes video on https://youtu.be/ZLIIYj2X-Qc about “Dimensions of Colour Today” and at at 21:26 in detail about various color wheels.
The RYB color wheel is indeed wrong and outdated. For Darktable v4.4.2 this does mean, that only Luv vectorscope does show correct complementary lines of RC, MG and BY through the white middle point. Vectorscope JzAzBz is also quite ok, but RYB is not at all correct. Please find attached an image with screenshots from Darktable and DaVinci-Resolve vectorscopes of a simple RGB test image.
For complementary colors (which have to add to white or gray!) the CIELUV vectorscope of Darktable is correct and of course also DaVinci vectorscope. In the CIE 1931 (and also the CIE 1976) diagram of DaVinci the correct complementary straight lines are also visible quite well.
As mentioned in my previous postings for “real” harmony, not only the straight line through white is important, but also the same perceived brightness. This second condition is not visible in the vectorscope and can not always be realized. See the circles in the CIE-1931 diagram of my posting dated Sep 27 with the MacAdam circles.