Thank you for the information.
Actually I didn't so stick to vanilla Vim and have no intention to avoid Neovim at all!
FYI, since this IME embeds a terminal emulator it should be able to use with other terminal-based editors (including Neovim) by applying almost no changes to the editor's codebase.
I'm not familiar with how IMEs work in Wayland at the moment, but I guess it is possible by the similar way as XIM.
I would like to investigate the protocol later.
FYI, since this IME embeds a terminal emulator it should be able to use with other terminal-based editors (including Neovim) by applying almost no changes to the editor's codebase.