Thanks, that fixed it! I went to /etc/apache2/sites-available and edited the 000-default-le-ssl.conf file to comment out all lines for the <VirtualHost *:443> section. Once I restarted apache and ran certbot --apache again, I was able to get a new cert.
All the images stopped showing, I presume it was because they still had their address as linuxhomeserver.duckdns.org. Once I used a plugin to change all the links to the new .com address they are showing again. Thanks for your help on this.