SSH can actually do that.
How does what you say "SSH" accomplish server to server transfer without exposing credentials of one server to another?
Using something like magic wormhole[2] could work. SSH to both sides and run the required commands.
[1] https://matrix.org/blog/2019/05/08/post-mortem-and-remediati...
[2] https://magic-wormhole.readthedocs.io/en/latest/welcome.html
Also SSH can be configured to use different keys for each server.
~scp is also deprecated on multiple platforms.~ https://www.redhat.com/en/blog/openssh-scp-deprecation-rhel-...