Basically giving the option to switch to WYSIWYG <-> Block-Editor – So you cover both use cases!
Hi I see @petschko is another option to switch between the Classic and Gutenberg editor. If you have the two plugins active, you can go to Settings > Writing
to enable the option to Allow users to switch editors.
You will then be able to use page settings to switch between the classic and block editors as shown in this short video.
Alternatively, I sometimes using the Classic Editor block when I editing content on the block editor.
I am not sure if this helps, if you were thinking of something different please let me know.