I looked into this with Zoom, because I wanted to have a nice background like my online bridge partner does. It turns out that Zoom does have a way to separate foreground from background that does not rely on a green screen. It mostly works although there are a few artifacts. However, this feature is only available on Windows. If you are running it on Linux, you need a green screen in order to use a virtual background.

I use an old slide projector screen with a green cloth draped over it. It works well but is a pain to set up for every Zoom call.

--Greg