I've written a plugin that should make this easier for MTK based kobo ereaders, aka Libra Colour and Clara Colour.
Have a look here:
https://ogkevin.github.io/kobo.koplu...bluetooth.html
It esentially allows for registering key bindings via the UI.
The messages/UI needs a bit of polishing tho. But I think the concept works, and can be tested/played around with in the meanwhile if interested.
This might also be of interest:
https://ogkevin.github.io/kobo.koplu...bluetooth.html