Why don’t you try to talk with the korean manufacturer BEFINE which make thin silicon keyboards skins in every languages to have your keyboard as a standard in their collection ?
a) integrated within the laptop (and hence not separate and wireless and battery powered), and
b) completely customizable (I get the impression that existing devices on the market only do one layout).
This particular one is kind of slow… from 2015 beginnings… not sure the tech is good we don’t see it much around and we should because in the end it’s less material = cheaper to produce so it’s probably not easy to achieve a good one.
personaly I wouldn’t care what is written on the keys. But I need a ISO-Layout. Not an ASCI Layout. Best way imho would be to just split the bigger keys (like the left down shift on ASCI) into two keys. that way noone would miss any keys. And extra keys are allways welcome.