Hey, thanks for answer.
I’m using a selfmade theme. To use the Gutenberg Editor would mean that I have to change massive things in the theme to make it compatible.
My fontsizes and headlines are orientated to the classic editor (paragraph, heading 1 to 6 (h1-h6)). Gutenberg S M L XL is using IDs and not H-Defaults.
(Sorry for my bad english)