How can I customize a Gutenberg Block beyond the given options?

Gutenberg blocks show almost all available options. Some options that are available as shortcode parameters, however, would slow down loading the block or extremely extend the menu. We therefore decided to omit them.

In other cases we limited the scope of available values so that sliders and menus would still be useable.

Screenshot - Gutenberg menu - transform into shortcode - WordPress

If you need to go beyond these limits, you have to transform the block into a shortcode. All settings that are not default will be carried over into the shortcode.

Please note that you cannot convert the shortcode back into a block. If you want to return, you can use Gutenberg’s “Undo” button. If a block type can appear more than once on a page, you can also duplicate it first and keep one as a backup until you know you are happy with the result.