COVID-19 got everybody to create and upload content. If you are just using your webcam, you need nothing more. If you want to up the quality, you need a DSLR or a mirrorless camera to utilize the bigger sensors, better lenses and nicer overall look.
Most “serious” cameras, though, can not operate as webcams and need a gizmo called a capture card. It’s a device that turns your camera’s HDMI output into a stream that a computer can take via its USB port. Elegato HD60 series (ranging from $179 to $350) is a family of such devices for example. But! Sigma took the Sigma fp a step further and you can use it as a webcam right out of the box. Sigma’s blog details the exact steps to use the fp as a webcam.