I came up with a solution using IPC::Open3 before reading your posting with more care. I am new to Capture::Tiny and thank you for the introduction. IPC::Open3 also works but Capture::Tiny can provide something simpler. Your code is interesting pedagogically but the example is as complicated as an open3 solution and maybe a little overkill for the problem.

use strict;
use warnings;

use Capture::Tiny 'capture_merged';
my $python_ver = capture_merged { system('python', '-V') };
print "Python version is: $python_ver\n";
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