[JNRowe]

That seems potentially unpredictable versus building the string and calling cd once. For example, if you use direnv-type tools there may be side-effects along the route¹. zsh users could have state changing via the chpwd functions too, although that could be mitigated with "cd -q" at least.

Obviously, it might not be an issue for your use, but just noting a potential gotcha if I were to lift it for example.

[ Golf-y zsh, because vacation time and AoC has finished: ..() { cd ../${(pj:/:)${@/*/..}} } ]

¹ even just expensive setup/teardown delays would feel odd*