It's not a site that's internet facing, because it's an internal reporting site for aid projects containing sensitive data.
To be honest I was forced into metabox because it supports grid builder and I needed faceted filtering, so I had to find a way to replace Essential Grid which has its own meta engine.
I went down this route to do without an additional plugin. What I didn't realise was that you had to add the php to functions manually (FYI your generated php is missing '' in several places, which results in errors). Once I'd done that I got the post type back but without the ability to edit posts. At that point, I gave up and went back to CPTUI - it's just better/easier than mucking around with functions every 5 minutes.
Also, I can't deal with mission-critical support that gets one reply every 24 hours. I have clients to satisfy.
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