I am eagerly looking forward to WordPress 5.9 and enjoyed giving the Full Site Editing experience a spin on WordPress.com, before it gets released as a part of core. As we speak and read here, there are continuous iterations being done to this feature and also the Gutenberg Block Editor.
The Full site editing (FSE) feature will allow users to make finer changes to the header, footer, and various templates of the site’s theme from within the editor itself. These changes can be made using the highly modular block editor.
The easiest way to try out the feature is to create a free website on WordPress.com. Opt in to the beta full site editing experience during the sign-up process. Install a full site editing ready theme like Blockbase or Zoologist. There are some excellent tutorials linked in the WordPress.com support docs to get you started.
In my case, I did a rather simple exercise of trying to replicate a header layout I had created sometime back on Figma, into the blockbase theme. It took me maybe half-hour, (including time to learn and tweak things to get a look close to what I had designed) . I tweaked the menu to a small vertical format too without much effort. The theme has a single font, however I was able to play with the letter spacing, and font weight to get different shapes, sizes and emphasis. I had fun with it and can only imagine how the possibilities are unlimited with a simple minimal theme and the power of Gutenberg blocks.
Overall, the whole experience did indicate a learning curve which I hope will get more flatter, as the interface becomes more and more intuitive with so many contributors working every minute to make it better! Thank you, WordPress contributors, you are awesome!