if already pushed then you'll need to --force it, since you're effectively rewriting history
It is not recommended because if someone else had pulled the changes after you pushed to remote, then they will have a hard time pushing their changes once you ammend a commit and force push to remote.
For the last point,
It is not recommended because if someone else had pulled the changes after you pushed to remote, then they will have a hard time pushing their changes once you ammend a commit and
forcepush to remote.Definitely true. More so applicable for your own branches. Terrible if branches are either shared or common branches are needed.