So I tried everything and every plugin to fix my issue and expose the list CPT data instead of showing brackets [ ].
And the answer is something that might be a bug in WordPress Rest API.
The problem was I am using custom statuses and none of my posts were assigned as default WordPress status. After changing the posts to any of the default built-in statuses, it worked. But doesn’t work for custom statuses it seems…. at least not with custom statuses created with a plugin called PublishPress.. Perhaps it just doesn’t work with custom statuses at all, all-around
Hope this can help someone else!