Typically, as in with native wayland apps, hyprexpo works perfectly fine with fullscreen apps. You can be on a workspace with a fullscreen app and hit your expo keybind and see all of your workspaces. When an app is running through XWayland, however, it does not give up fullscreen and remains on the screen while all of the event listeners for the expo are getting input. (you click where another workspace would be on the screen and it takes you there)
I can provide a recording of this if I wanna deal with OBS (it runs super slow on my machine :( ), but this should be pretty easily recreated on any other machine.