The key idea is to have many differently named shells. Typically, I group them by project (common prefix name), and the projects live in directories. I have some hacks to organize ibuffer, to split frames, to reflow buffers in the existing windows (eg to organize related project buffers (shells, magit, dired), or to show shells from multiple projects, or selected buffers, and so on). Emacs’ natural frame splitting and buffer selecting/switching commands are good enough if you dont display more than four buffers at a time, but soon you may need to show 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24 or have funky arrangements, so you may collect functions to help along splitting n*m grids or keeping useful splits. The shells work very organically inside Emacs and you can still use it as a text editor. The so-called “dumb terminal” in M-x shell is a thing of beauty as it really is just a text buffer like any other; I think of it as a bash repl. If you are used to curses TUI commands it may not work, so for these rare occasions I also use eat (but tend to avoid). See also answer to a sibling comment.

Not sure, tbh. I use emacs -daemon to start a server; emacsclient -nw to connect. I use ssh and start a server on the remote. I spawn multiple shells with infinte buffer size and dumb terminals (M-x shell) so I can seamlessly edit. (These are based on comint, a neat command interpreter.) I use my own hacks for named shells (https://github.com/pjj/Emacs-nsh) and for rearranging/splitting windows, but any of the latest powerful LLMs can help with ergonomic modifications to M-x shell or the various improved terminal emulators (vterm, eat, ansi-term) or with renaming and moving/splitting windows. The Emacs manual is excellent but long; worth it IMHO, but focus on things you use. The tutorial is quick; worth it. I avoid curses programs (fancy TUI) or write wrappers around some of them. I love the -p option in codex/claude/copilot.

It's just too bad Emacs doesn't also include a decent text editor, right?