With slightly fewer manipulations:

Win8 Strawberry 5.8.9.5 (32)  Thu 09/21/2023 16:18:12
C:\@Work\Perl\monks
>perl -wMstrict -le "
my @l = ('abc', 'cd', 'e', 'fg', 'hi', 'hello world');
print length pack '(A*)*', @l;"
21
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