A jump host is just a system that serves as an exit point into the restricted network. You can do this with Ubuntu desktop but you need to figure out how you are going to jump into your host. Others have mentioned tail scale and head scale as options for doing this. Tailscale would be an example of an agent based adhoc vpn solution; this would place a dependency on an external provider to host a connection broker service and use an agent that periodically checks into the broker service for connection requests. Headscale would be the self hosted option and you would need to forward a port into your network and you should guard it with a reverse proxy.