You're overcomplicating this. A module is basically just a hunk of Perl code that makes use of the package keyword. This code can be executed directly from a scalar by using eval:

~/src/tmp$ cat dynamod
#!/usr/bin/env perl

use strict;
use warnings;
use 5.010;

my $mod_source = 'package Foo; sub bar { say q(Hello, world!) }';

eval $mod_source;
Foo::bar();

~/src/tmp$ ./dynamod 
Hello, world!
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