In which directory install Composer on a shared linux server: ~/bin or /home/username/bin or /usr/local/bin or public_html?

Which directory is the best to use for installation on a shared linux server?

Some instructions say to create a “bin” directory (mkdir bin) and to install Composer in it?
That would be the [~/bin] directory, which apparently is the same as /home/username/bin ?

Some say in the /usr/local/bin folder – how does that relate to /home/username/bin ?

Some say in the public_html folder (is that the same as home/username/public_html ?)

Drupal version: