Gutenberg is good if you're simply writing a normal blog post. A fantastic improvement over the Classic Editor, as those people who aren't techy can now easily add more complex stuff to the post. Up until now they basically could only add font color.
But if you're a power user then it's not for you as it doesn't function well on pages that are to be a mix of Wordpress content and custom code. I usually just install Classic Editor right away and set it to default for all new posts.
Of course, if you want more control over your actual page and want to create layouts, boxes, etc., then again Gutenberg is no good as you'll be using some page builder.
Professional bizdev can help you, the affiliate, to negotiate better terms with casinos. PM for details and a free evaluation of what I can do for you. All geos.