Alternative: Elgato camlink hdmi capture interface with a used Sony A6000 system camera is one way to het better quality. Its about sensor size and optics. A mirrorless system camera has for example APS-C sensor which captures much more light than a typical web cam sensor.
Gphoto2 camera to webcam capture tool if you are runnning Linux. Then you can turn system cameras into webcam given the right camera model.
From a quick look that is about 500€? (100 for the capture and about 400 for the cam on ebay). Also, you probably still want a stand, battery, lighting, microphone...
That is at least 5 times as expensive as a webcam. Is it at least 5 times as good?
If you already have a system camera, that might be a good alternative, but otherwise?
Gphoto2 camera to webcam capture tool if you are runnning Linux. Then you can turn system cameras into webcam given the right camera model.