"how to make this conditional, either hyphen (-) or I want to say en dash(–)?"

Just replace the single hyphen in your regex with a character class containing all possible dashes, hyphens, etc. In the character class, always put an ASCII hyphen as the last character or you'll generate a range. See perlrecharclass and, in particular, the "Bracketed Character Classes" section for much more detailed information.

An example script follows but, first, some notes:

• The open pragma indicates that output to stdout should use UTF-8. This also avoids the "Wide character in print ..." warning.
• I've used a mix of \x{...} and \N{...} to show some alternatives. Don't do this in your real code as it's likely to be confusing: pick one format and stick with that.

#!/usr/bin/env perl

use strict;
use warnings;
use open OUT => qw{:encoding(UTF-8) :std};

my ($en_dash, $em_dash) = ("\x{2013}", "\N{EM DASH}");
my $str = "a-b${en_dash}c${em_dash}d";
my $re = qr{[\N{EN DASH}\x{2014}-]};
print "Original string: $str\n";
print "Parts separated by some dash:\n";
print "$_\n" for split $re, $str;
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Output:

Original string: a-b–c—d
Parts separated by some dash:
a
b
c
d
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Because the hyphen and dashes are not easily distinguishable, here's the same output piped through cat -vet. Don't worry too much if you don't understand the codes; just notice that they are different.

$ ./pm_11137036_re_alt_dashes.pl | cat -vet
Original string: a-bM-bM-^@M-^ScM-bM-^@M-^Td$
Parts separated by some dash:$
a$
b$
c$
d$
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See also these Unicode® resources: the PDF "Code Chart: General Punctuation -- Range: 2000–206F"; and, for characters referenced therein but not in that range, "Unicode 14.0 Character Code Charts" (note the "Find chart by hex code:" near the top of the page).