I tried starship a few years ago and found it too "extra" and sluggish. I'm sure it may have improved in this time, but I ended up sticking with the excellent Hydro[0], only for fish though.

It's very minimal while having useful features: - exit codes, even for pipelines - git branch, status (displayed as a dot if your tree is dirty) and ahead/behind counts - command execution time (if above some configurable threshold) - truncated/minified $CWD, always maintaining the git root's name (I sometimes like it, sometimes don't; fortunately, it's very easy to change) - current vi-like mode (I don't use that)

It's very fast and async (prompt repaints don't block your input or running commands), and totals 132 lines of fish (according to cloc[1]). It's also very customisable through variables, which can be declared as universal to instantly change on all sessions you have open.

If you're on fish and like this feature set, definitely give it a shot, or at least look at the code as a base for a bespoke prompt :P

[0]: https://github.com/jorgebucaran/hydro [1]: https://github.com/AlDanial/cloc