You may also be interested in looking at https://www.oilshell.org/ . Like yours, it's an effort to make a 'better bash', and he has a lot of posts discussing various aspects of Bash syntax and shells in general, and how to improve them.
Yeah, Oil shell is great. I got a lot of inspiration and learn how things work by reading those posts. I try to tackle it by a different approch by leveraging Clojure syntax for the programming bits but keeping things compatible for the command execution uses.
