Easy peasy.

$s = 'a,b,"hey, you","str1, str2, str3",end';
push @fields, $1 while $s =~ /("[^"]+"|[^",]+)(?:,|$)/g;
print "$_\n" for @fields;
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or

$s = 'a,b,"hey, you","str1, str2, str3",end';
@fields = $s =~ /("[^"]+"|[^,]+)(?:,|$)/g;  # Use +, not *, or you get
+ a blank element
print "$_\n" for @fields;
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Both print:

a
b
"hey, you"
"str1, str2, str3"
end
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