Accented letters vs. keyboard shortcuts

Windows 10 x64
MuseScore 3.6.0
Keyboard layout: Microsoft Canadian Multilingual Standard (CMS)

At the moment I'm working with Icelandic text. In MuseScore with default settings, the characters 'ÁáÉéíÓ' are ok, but I can't type 'ÍóÚú'. In MuseScore preferences, the vowels that work are assigned as keyboard shortcuts (A, Shift+A, E, Shift+E, I and Shift+O); The vowels that don't work, are not (Shift+I, O, U and Shift+U).

I then assigned U as a shortcut for something and then was able to type 'ú'. Therefore, assigning these letters to random things seems to be a viable workaround.

In CMS, right control and alt (rCtrl and rAlt) are used for typing extended characters, while left control and alt (lCtrl and lAlt) are for keyboard shortcuts. You have to type rCtrl+; to prepare the aigu accent (´), followed by the vowel to type the character. For example:
rCtrl+; followed by A types 'á'
rCtrl+; followed by Shift+A types 'Á'
rCtrl+; followed by spacebar types the character ´. This is unimportant to me, but incidentally, it doesn't work in lyrics either, because the spacebar advances to the next syllable instead of typing the character.

Ctrl+; is not assigned as a shortcut. It can't be assigned while CMS is active. If it is assigned using another keyboard layout, then upon returning to CMS, it has no effect (the shortcut doesn't work, and typing accented letters is unaffected). I'm ok with this behaviour.

You can type dozens of languages with CMS, but it was primarily created for the Canadian market, and the most common characters for French 'ÉéÈèÇçÀà' have dedicated keys, so it's really less impractical than I might be making it sound. It's handy for working in multiple languages, and it also has the extended punctuation needed for programming, unlike most French layouts.