Thank you for your suggestions.

At the end, my original script works using both:

my $MYPath = Win32::GetANSIPathName ($path);
my $MYPath = shortpathL ($path);
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However, $MYPath cannot be in the same folder as the script itself! Moving it somewhere else, for example on the Desktop, and reading it with:

my $PathDesktop = File::HomeDir->my_desktop;
my $MYPath= $PathDesktop . "\\Ршзеф&#109
+2;.xlsx";
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allows the script to work fine.

The idea of copying the file with a 'simple' file name is worth using, as it is simple and effective. Direct reading the file handle did not work for me.