Hendrik Luehrsen shares stats and notes about 100 FSE themes in the WordPress repo by 53 different contributors. He notes that, excluding the Twenty Twenty-Two theme, “all remaining 99 FSE themes combined have about 30,000 active installs, rising fast!”
Hendrik encourages others to: “Build stuff with the FSE themes! Break stuff. Explore limits. Break those! Gather experience! And talk/blog/tweet about it!”
Re: Full Site Editing, the Make WordPress Test Team has called for testing around category customization.
And member Eric Karkovack shares How to Create a Block Theme Within WordPress.