Figured it out. User error.
- The default Romanian keyboard layout is
ro(std)notro. The former is equivalent tousexcept it has Romanian characters on dead keys. That made it feel like nothing was changing. - It is enough to modify
~/.config/niri/config.kdl.services.xserver.xkbis NOT needed when using niri 25.05.1. - There’s a recent commit in niri which allows it to read xkb settings. Future releases might allow us to configure keyboard layout from either location. Right now follow, the niri docs are correct (provided I’m not dumb enough to use the wrong keyboard).