I use Manjaro with Deepin on an old MacBook with a German keyboard. I have set as a "German (Macintosh, no dead keys)" which is kind of usable, even if it does not allow me to access the alt keys imprinted on the keys (for instance the @ symbol is alt+q and not, as indicated on my keyboard alt+l). I can live with that.
But as I write Portuguese texts on a regular basis, I need to input the ñ and the ç characters all the time. These keys simply do not seem to exist on this keyboard, independent of any modifier keys. However, there are keys I have never used in my whole life, which I gladly would exchange for them, such as ¢ or ć and ń.
Which is the simplest way to achieve this? Or anything similar? Hacking in utf codes is not an option and appending different keyboards as well- this is after all a notebook.