Just use magit and easily make fixup! commits with like 3 key presses. Even if you don't use emacs keeping it around just to use magit is worth it.
Edamagit for vscode users is not as good but it does this particular workflow great.
Edamagit for vscode users is not as good but it does this particular workflow great.
fixup is "stage changes, users selects past commit to fixup, commit staged changes"
absorb is "stage changes, git-absorb figures out which past commit to fixup, commit staged changes"