I've found the author of Voynich manuscript. He was Giovanni Aurispa.

[Aga Tentakulus]

   
"Example: the four-character word kchsy is converted to a 10-character word"
What happens if only half of a character (EVA ch) is displayed?
Doesn't that make it 2 letters? That would make it 5 characters.
Sometimes we forget the diversity of the VM text.
   
For example, the endings with an arc also mean more letters. And it is also not mandatory that they only have to be at the end of a word, as various texts in other books prove.
It is well known that (Eva 9) can also mean -us / -um. No matter whether German or Latin. That's 2 again.
Now there are already 7 letters. The thing is, once you have fixed it, it is difficult to change it.
Stay away from a one-to-one translation.