However, what I am suspecting is that you may not see this already because you didn’t enable E2EE metadata yet, do you see in Organisation Settings a “Get started” menu ? If that’s the case, you can follow what’s written there to enable E2EE metadata, this will also allow you to use more custom content types such as custom fields, multiple URIs, etc.
You can also take a look at this blog article. Don’t hesitate if I can help any further
In Metadata Key, as you can see at the very bottom of your screen, you will need to generate a Metadata Key and keep the selected field for “Metadata key policy” and “Zero knowledge”. Then in Encrypted metadata menu, make sure to enable “Enable encrypted metadata (recommended)” You can also untick “Enable legacy cleartext metadata” if you prefer that your users uses E2EE metadata, this is optionnal though.
Furthermore, you will be able to convert cleartext metadata to encrypted metadata in Migrate metdata menu.
So far, no there is no more customization than that. If you have ideas or want some more features, don’t hesitate to open a feature request in the forum.