OsixthreeO is a multi-purpose theme for WordPress. It has lots of controls and a nifty custom header. Eventually there will be extensions available.
This theme began as my go-to starter theme which has been evolving since 2015. Each time I discover something new or better or more efficient, it goes into my starter theme. It is originally based on Underscores (_s), the starter theme from Automatic, as such I keep tabs on _s to be sure this theme is all up to snuff with all the new stuff. It also draws heavily on ideas from Genesis and EA Starter.
The block editor is kicking major butt and slowly evolving the WordPress admin. OsixthreeO loves the block editor! It can be difficult keeping up with the constant flow of changes and additions to the editor.
Overall the block editor is an excellent improvement over the old title/content block interface. There are plans for the block editor to take over the entire website – header, footer, widgets, sidebars, etc… This will obviously change the role a theme plays in the overall scheme. OsixthreeO, with it’s header, font and color controls, probably won’t be able to follow the evolution of the block editor when it (eventually?) takes over the entire website.
We don’t know when full site block editing will happen. Probably not for years! And the idea will evolve and change.
So, in the meantime, use OsixthreeO. You will enjoy a manageable header, customizable custom header area with background image and/or color gradient controls, font, color, shading and many other controls at your finger tips.