Thank you both so much! I ran cpan as you suggested (perl -MCPAN -e shell) and without sudo at the beginning of the command (mostly because I forgot to put it there). This seemed to prompt it to reconfigure itself, as it gave me some setup dialogue when it started.

With that change, it successfully installed LWP::Simple and Bundle::CPAN.

Such a relief!

THANK YOU! This has been making me insane for weeks. I'm so relieved. Thank you.