In Spacemacs, it seems I can get the effect by pressing Ctl-h, but what I want is this to be the default behavior when pressing backspace.

Probably dired-up-directory?

You can use ^ to jump up. That said, one of the packages I have installed (ivy?) enables the mode you're asking about - pressing delete/backspace removes a single path segment not a single character

Ido does this https://www.masteringemacs.org/article/introduction-to-ido-mode

(defun tvaughan/parent-directory (path)
  "Return the parent directory of PATH."
  (or (file-name-directory (directory-file-name path)) ""))

(defun tvaughan/backward-delete-directory (arg)
  "Delete characters backward until encountering the end of a word.
With ARG, do this that many times."
  (interactive "p")
  (let ((contents (minibuffer-contents)))
    (delete-minibuffer-contents)
    (insert (tvaughan/parent-directory contents))))

(use-package selectrum
  :config
  (selectrum-mode +1))

(define-key selectrum-minibuffer-map (kbd "DEL") #'tvaughan/backward-delete-directory)

ido does this much better. This still doesn't replicate it as well. Granted, this is used with selectrum, but should be adaptable

Is Ido basically a competitor for help or ivy?

Thanks @U01KUQRDMLG after adding ivy, and now I get the desired effect that I want. I am trying a new config and can’t remember how this work with my old config. And ivy package seems to be the one that I really need.