I would rather solve file access at an entirely different level. A filesystem is a reasonable, editor-agnostic abstraction for this, and I can use sshfs to mount a remote directory over SSH in a way that's invisible to whatever tools I prefer to use to edit the files.

If you have a jumphost chain, you can configure that in the SSH config.

I don't know what a devcontainer is exactly, but if it's a container in the sense that it runs a Linux development system, I would investigate whether that, too, could easily be set up for access via SSH or mounted locally through some other mechanism.