Modern browsers happily show you the actual characters, while sending their encoded entities to the server. So, from a user perspective there is no ASCII limitation. Case in point: söhne.at (just some random website, I have no idea what they are or if they are legitimate)
Also, Kanban was invented in the 40s as a process for automotive production lines. That’s why it aligns so well with maintenance and operations projects in IT. It’s ridiculous how more and more people claim it comes from software development and would not fit hardware projects, when that’s the core use case of the methodology.