If you want to use letsencrypt with a cPanel server (that does not have build-in plugins for certificates) is going to be the same frustration.
However.... You've followed the wrong guide in this case. You should use Simple guide to add TLS cert to cpanel · acmesh-official/acme.sh Wiki · GitHub instead of others.
If you still want to move to a new provider, please consider the providers on the below list, since they provide letsencrypt certificate in an automated fashion.
Thank you