In reply to ZigPress.

Yeah it’s probably good to point out that “Gutenberg” is a lot more than an Editor. It’s also a CSS framework (powered by theme.json), block based themes (aka FSE), and blocks+blockEditor. The classic editor plugin just replaces the block editor with tinyMCE. It does not disable things like SVG tags for duotones being output on the frontend of every WP site (whether you use them or don’t). If you don’t plan to use things like duotones or the WP css framework (theme.json), you probably want to be looking at the Disable Gutenberg plugin, not Classic Editor.