Cannot connect to git.drupalcode.org (SSH port 22) from multiple diverse locations - Connection Timed Out

Where did you see instructions to use git@git.drupalcode.org?

That is not listed as a remote URI on pages like https://git.drupalcode.org/project/drupal or on https://www.drupal.org/project/drupal/git-instructions → and is not a domain that accepts SSH connections.

https://www.drupal.org/drupalorg/docs/user-accounts/git-authentication-f... →
Authentication methods for Drupal.org’s Git repositories changed March 2019. In particular:
Git remotes have changed
SSH keys are now recommended for all authentication needs
Changing Git remotes
If you are a maintainer who has an established Git remote in the format @git.drupal.org:project/.git, the format should be changed to git@git.drupal.org:project/.git.
Sandbox projects
HTTP clones for sandbox projects changed from: https://git.drupal.org/sandbox//
.git to: https://git.drupal.org/sandbox/-
.git
I didn't realize SSH was required for telnet or traceroute.

I don’t see git@git.drupalcode.org mentioned on that page either.

Regardless, this is not something we can change, git.drupalcode.org is fronted by a CDN, which forwards HTTP connections, not SSH. So swapping the protocol used without getting the full documented Git remote URI will not work.