From the perspective here, if you aren’t using MiaB, it is out of our hands to troubleshoot your problem.
However, you abandoned MiaB as we were narrowing in on the exact problem. It probably would have been better to post here as soon as you discovered the problem.
Absolutely understandable. At this point, I suspect that you may be disillusioned with MiaB and I understand that. But the question should be asked … where do you want to go from here?
If you’ll be content to stick with the cPanel hosting you are using, that is your choice. But, if you’d prefer to get back to using MiaB then that is completely attainable.
You mentioned that the project was working for you well with OpenVZ which surprises me as I have never had an instance of MiaB function properly using OpenVZ. I cannot find on your web host’s site any information about the current hosting method which is useful, so I am of the mind that they perhaps simply moved to the newer version of OpenVZ, which again, doesn’t work reliably for MiaB.
One thing though, as much as I do not like NameCheap, they have done everything correctly. The problem lies within your MiaB instance as it is not responding to DNS inquiries. The Glue records are set up properly and are working (well at least before you switched to cPanel) so following up further is nothing more than a exercise in frustration for you and them.
What could you have done to get back on track asap? You could have simply moved DNS for the aaronweiss.me domain to another provider. Had we actually have been able to communicate in real time, I would have asked you to trouble shoot a couple of things from the command line and if a solution was not found in a few minutes, had you create DNS elsewhere. As MiaB uses two dns server clients I suspect that may have been a sufficient solution. But at this point, what is done is done and the only question is what is the path forward.
Personally, I would move to a different provider, restore my backup, migrate my new email from the cPanel hosting so that all of my emails are together, and carry on with MiaB. But that is me. What do you want to do? I and others here in the community will be willing to help. But we need to be able to communicate in real time.