"...I found it gave a lot of warnings for empty cells and it did not even handle the utf-8 euro symbol at all"

Emphasis mine. From rt://40061:

'The Euro symbol isn't stored in Excel as a single character. It is stored as a UTF-16 character and is returned by Spreadsheet::ParseExcel as a Perl utf8 character.'

'This is what you are seeing and in terms of the way Spreadsheet::ParseExcel handles Unicode it is the correct behaviour.'

'How you should handle the utf8 string from there depends on what you want to do with it.'

further on..

"I've come to the conclusion the there is no great solution for parsing Excel files with Perl. That makes me sad. "

If you are saddened by what is available, extend what's there or write your own. Alternatively Spreadsheet::Read:

#!/usr/bin/perl

use strict;
use warnings;
use feature 'say';

use Spreadsheet::Read;
use open ':std', ':encoding(UTF-8)';

my $book  = ReadData('euro.xlsx');
my $cell  = $book->[1]{A1};

say $cell;
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Output:

€40
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