Instead of using complex code to make sort efficient, use Sort::Key which handles that for you without the messy code.

use File::Slurper qw( read_text );
use Sort::Key     qw( rikeysort );

print
   rikeysort { ( /(\d+)%/ )[0] }
      split /^(?=>>> )/m,
         read_text( 'try3.txt' );
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(Also note the more reliable split pattern.)

Features:

• Simplicity.

• It's a stable sort, meaning it keeps the relative order of already-sorted items.^[1]

• And it might be the fastest of all provided solutions.

  And it's also the fastest of all the provided solutions!

1. The builtin-sort on modern versions of Perl is a stable sort. And this means the provided ST solution is a stable sort on modern version of Perl. But the provided GRT solution isn't a stable sort.