Use case is important, to determine what resources+tools you have access to/can deploy. However, assuming this device/VM runs "unix", and to K.I.S.S., use reve

Use case is important, to determine what resources+tools you have access to/can deploy. However, assuming this device/VM runs "unix", and to K.I.S.S., use reverse SSH tunnelling. Once an SSH tunnel is established on your side, you can do whatever you want... e.g. tunnel VNC through for GUI. You can of course add more layers of security e.g. non-standard SSH port, dedicated VM/server for the SSH entry point, refresh SSH keys regularly etc.