The letter ‘K’ as a mark of origin?

[Petrasti]

If we look at the manuscript and the letters, we see the k, which is transcribed as ‘k’ in EVA. As the letters have similarities with the Latin script, the ‘k’ as such is also recognised as ‘k’. (of course it could be something else, so any issue is debatable until the final solution). In EVA the ch is transcribed as "ch", which I personally see differently, because if the ch is a "ch", we would have to find some more words that are written with "c". But these are rare. So if the scribes used the letter “K” as a consonant instead of the “C”, the question is, in which region was a "K" used instead of a "C"? Or in which language in the period between 1380-1460 was the “K” used instead of the “C”?  So it doesn't matter whether we start from a natural language or a cipher, even with a cipher the question is the same: why did the scribes use the “K” and not the “C”? If it were a Latin script, wouldn't the “K” be predominantly a “C”? The same applies to the Romance languages, as they were modelled on the Latin script tradition.