Why can't I find a 3rd party product to send emails that works?

*sigh* it should not be that difficult.

So far, I have tried:

• SendGrid:  They seemed to work.  However, I inadvertently spun up a new project and committed my SendGrid API Key in my source code to GitHub.  Apparently they like being Big Brother and scan GitHub for their API Keys and shut down accounts when they find it.  Great.  Shut down my account, that's fine I'm moving on ...
• MailGun: This did ... not ... work.  I walked it in the debugger, no errors, went through all their documentation.  Just did not work. I don't have the time, patience, or bandwidth to make it work.
• SparkPost: My current attempt.  Really hoping 3rd time is a charm.