JJ lacks too many features compared to git, it's easier to use but just less powerful. I think Helix and Zellij are good for that "batteries included" approach, but neovim and tmux are more powerful and allow much more customization IMO so those tools don't displace them for me. I think shell choices are less impactful, if you're writing scripts 90% of the time it'll have to be bash anyway, use what you like for the interactive shell though.