Tmux-xpanes: tmux-based terminal divider
github.com
github.com
This appears to way easier to do tricky things super fast than the wildly obscure language needed to write a small script, and its literally just a bash script itself, meaning it's as portable as almost anything. I love it.
Thank you OP! (Assuming you are the author of the tool given usernames here and github)
For one, you still need to manually inspect each window and issue further commands.