Disable comments on objects of certain class

There's no such built-in configuration option. If this is a hard requirement, you could perhaps remove any comment before the changes are saved to the server (for instance Property Calculator might be able to do this). However users may get confused about where their comment went with this approach. You may want to add some instruction texts to the metadata card to notify them that commenting is not allowed for these objects.

Thank you:)

Thank you:)