I'm having a similar issue with my client's wordpress site also hosted on GoDaddy. "the_content" just recently stopped working. I have reviewed the code, and everything seems to be in line with the information I have found regarding "the_content" and it's use. I was upgraded to Gutenberg, but that was a while ago and it was working. Now it's using wp version 5.2.2, and I have no idea why it's suddenly stopped working. I can the new "block" editor's content to post, but not via the_content. Really strange.
I hate to say it, but I suspect it has something to do with GoDaddy's "Managed Wordpress" hosting service which autoupdates wordpress core and god knows what else. It also has sucuri's firewall added to the site via GoDaddy if that helps fill in some of the gaps on what else might be happening.