Can I set private custom block?

Hi, I'm using Drupal 8 and I'm thinking of introducing Gutenberg Editor.
I want to set up a private custom block without Gutenberg cloud.
It was easy on Wordpress.
Can I set up it on Drupal like Wordpress?

Maybe this question is same as this issue.
https://github.com/front/drupal-gutenberg/issues/7
But it's a little old, so please tell me the information if you have the latest.