That configuration file is quite broken and is causing your webserver to not work. I’m really puzzled as to how the apachectl command ended up inside that file.
Are you comfortable enough with the command line to edit that file? It’s salvageable, you need to make these changes:
Replace the ServerName line with ServerName clsindustriesllc.com
Which should allow you to reach your webserver again.
Once again, try to run the apachectl -t -D DUMP_VHOSTS command, making sure you are not in nano or any other text editor, or running Certbot when you do it. I just want to see what it says.
Your WordPress installation is actually located in /var/www/html.old/html
Your webserver thinks it’s in /var/www/html
The result is that your webserver is looking in a non-existent location, so you get the 404 error.
Why are you in this situation? Who knows. Maybe it’s your own doing, or maybe the DigitalOcean WordPress installer broke somehow.
The simple fix would be to edit the /etc/apache2/sites-enabled/000-default-le-ssl.conf file so that the configured DocumentRoot option points to the true WordPress location, but I don’t know if it’s the right fix, because I lack the context to understand how you got here in the first place.
In any case, your Let’s Encrypt SSL certificate is setup just fine, it’s WordPress that’s you’re having trouble with.