Comment by xk3

If you have systemd, you could do this:

    [Unit]
    Description=look ma, no autossh
    After=network.target
    
    [Service]
    Type=exec
    ExecStart=/usr/bin/ssh -o ServerAliveInterval=60 -o ExitOnForwardFailure=yes -Nn -R 7070:localhost:22 pc 'sleep 20m'
    Restart=always
    RestartSec=20
    RuntimeMaxSec=30m
    
    [Install]
    WantedBy=default.target