Metabox support does not seem to be enabled on custom post types yet, correct?

I've just tested a few sites of mine using metaboxes (using the excellent https://wordpress.org/plugins/custom-field-suite/) that I picked to be the least trouble migrating to Gutenberg. Currently, there are issues (for example: a WYSIWYG field renders as HTML) that would make this unusable for the client.

Overall, though, after months of concern it's an immense relief to see metabox support is finally starting to get some practical attention.