>Marathono is a small GUI tool that helps you manage long-running processes in macOS, so you don't have to maintain multiple windows/tabs/tmux sessions in your Terminal.
How about one tmux session and a couple of windows? You could name the windows perhaps. I could see how this might not scale, but I bet my socks someone else has found a way to script this and make it easy.
I know we don't want to be overly negative on HN, but this doesn't sound like a problem that needed a completely newly rolled solution.
So you have GUI output. What if I want to grep or save it to a file? I can see how this will be usable for people who aren't comfortable with a terminal--as a someone who transplated linux-to-mac, I know how terrible the terminal experience is on mac.
EDIT: below I was corrected that Marathono does all manipulating text output, +1.