You may want to consider minicpan (provided buy CPAN::Mini) to create and maintain an 'offline' cpan mirror. I do this for work, use the tool to create a mirror on a machine with internet access, transfer it to our offline network, point cpan/cpanm towards the files.

To export all modules etc just run cpan -a to create an 'autobundle'.pm package, which you can copy elsewhere and apply via perl -MCPAN -e 'install Bundle::Snapshot_2024_08_13_00'.