If you're using a wlroots compositor, then a workaround for sharing the whole screen is to use wf-recorder [1], which supports capturing the whole screen, and feeding its output to a virtual V4L2 device using v4l2loopback [2]. Software that is able to capture from a V4L2-compatible webcam (i.e. most) can them capture from the virtual device without knowing anything about Wayland. It's not exactly the most CPU-efficient way of doing things, but if you can afford the cycles it works very well!
[1] https://github.com/ammen99/wf-recorder
[2] https://github.com/umlaeute/v4l2loopback