I’m not sure if you can do it without authenticating on the remote. Have you seen sshuttle? Maybe you can run that on the remote to connect to the local machine. If the issue is that the remote “can’t see” the local machine to ssh into it then you could try something like reverse tunnel the ssh port to the remote, and then use sshuttle to connect to the local port that is forwarding traffic.
I’m not sure if you can do it without authenticating on the remote. Have you seen sshuttle? Maybe you can run that on the remote to connect to the local machine. If the issue is that the remote “can’t see” the local machine to ssh into it then you could try something like reverse tunnel the ssh port to the remote, and then use sshuttle to connect to the local port that is forwarding traffic.