Weston doesn't seem to implement that protocol while it's supposed to be the reference implementation, it's a bit worrying?
Weston only supports an older backwards-incompatible version of the protocol with an MR for v3. Input method/on screen keyboard on wayland is still kind of a WIP and there might be a backwards-compatible v3.2 in the future, but I'm not well versed in those discussions.
Is there anything else I can try this with that supports a similar kind of nested work mode in X11 environment?
Sway should work with `WLR_BACKENDS=x11` to run in x11. Maybe software rendering with `WLR_RENDERER=pixman WLR_RENDERER_FORCE_SOFTWARE=1` is needed if there are issues running it. I would recommend using fcitx5 as ibus until recently did not support the same protocol sway needs for compositor<->IM interaction so ibus might be hard to setup.