linuxmemes

Miryoku isn't a regular layout. It has things like keys that change what they do depending on whether you tap them or hold them. Maybe it's theoretically possible to implement it as a standard XKB layout, but it would not be fun. Usually, Miryoku is implemented in your keyboard firmware. But if your keyboard doesn't support flashing custom firmware (e.g. builtin laptop keyboard), then you have to use a software solution like kmonad, which is a daemon that has to run as root.

As a sidenote, even for some "standard" keyboard layouts there needs to be background process. For example, Chinese and Japanese have too many characters to fit on a keybaord, so they use something called an Input Method Editor. But those usually don't need root, in contrast to kmonad.