When using WordPress' current stable release, you can rely on the Tab key to quickly start composing:

1. Focus is set to the title as you open the editor.
2. Once you've added a title, you can hit Tab to quickly get to the main content area, where you'll be able to add blocks (by hitting / for example).

This changed with the current version of Gutenberg.

Steps to reproduce the behavior:

1. Go to Posts > Add New
2. Enter a post title
3. Hit Tab.
4. Start typing. It turns out you are not in the main content area.

Desktop (please complete the following information):

• OS: macOS Catalina
• Browser: Chrome
• Version: 77.0.3865.90