something simple:

my @sorted = sort {
    ($a =~ /(\d+)\D*$/)[0] <=> ($b =~ /(\d+)\D*$/)[0]
  } @filenames;
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and something simple and fast:

use Sort::Key qw(isortkey);

my @sorted = isortkey { /(\d+)\D*$/; $1 } @filenames;
[download]