> Not to mention that on Linux switching the locale may change the interpretation of filenames as characters, which isn’t the case with NTFS.
If you change the locale to an uninstalled one, then yes. But if the locale is installed, then I don't see a problem.
echo $LANG
# output: en_US.UTF-8
touch fusée.txt
LANG=fr_FR.UTF-8 ls
# output: 'fus'$'\303\251''e.txt'
sudo locale-gen fr_FR.UTF-8
sudo update-locale
LANG=fr_FR.UTF-8 ls
# output: fusée.txt
Are you maybe using non-UTF-8 locale?