Great job, I’ll really need this for WP 5.0

Gutenberg comnpletely mangles custom handmade HTML, which depends on being treated as raw HTML. If hand-coding or the classic TinyMCE editor is not enough or not right for a client, then I pep things up with a shortcodes plugin like shortcodes ultimate or even WP Bakery Pagebuilder. Gutenberg will basically trash all my strategies and I can’t rewrite all my client websites when 5.0 comes out. There is another plugin “Disable Gutenberg” but this one offers many more options. Sadly, neither of them offers to turn off Gutenberg on a per-page basis, which would be really nifty.