Welcome. Genius??? Far from it ... but you are not out of the woods yet. :| You have an a 'band aide' in place.
With that line for the theme in config.php that's the only theme you can use with the site.
Comment out the line you added for theme by putting // in front of that line. Save the file.
Hit site with browser. Still working?
So you didn't answer some questions ... on the re-install, did you use SoftTac again or used Moodle Docs instructions ( that you translated into cPanel-ese)?
If provider has a community forum, might want to post in that forum info on the 'band aide' provided here.
Other question ... did helpdesk of provider help? If they just pointed you to these forums without making any effort at all to assist, consider that provider might not be a good place to host a moodle.
Once installed, the journey has begun. By that I mean ... moodle will need to be updated or upgraded in the near future. May as well start to study up ...
https://docs.moodle.org/dev/Releases#Version_support (scroll down)
https://docs.moodle.org/dev/Releases#Moodle_3.6
https://docs.moodle.org/36/en/Upgrading
Along with that, do learn how to backup your site ... and study up on how to restore it where you host.
And do feel free to rate the posting that helped as 'Useful'. That helps me 'earn my badges' and thus another way to say 'thanks'.
'spirit of sharing', Ken