Kubernetes networking requires installing CNI plugin. Something simple like flannel will work fine and does not require any configuration. That's the only required addon for kubernetes, I think.
With docker you'll probably bind container port to the host. With kubernetes you can create Service of type NodePort and it's exactly the same.
Load balancing: I'm not really sure what do you mean, what do you use for docker load balancing? Just expose your kubernetes host to the Internet and that's about it. Or hide it behind separate reverse proxy, if you want.
Mounting directory from the host is supported with kubernetes, no problems here. Use hostPath volume in the pod spec.
Besides CNI networking potentially encompasses Services, Endpoints/Slices, Load Balancers, Ingresses and most recently the Gateway API. I'd say that's quite a bit complex.
Kubernetes allows you to make complex networking, which is especially useful for cluster setups involving multiple nodes. But if you're comparing kubernetes with docker, docker does not have load balancers, ingresses, so you can just skip it, if you feel that it's too much of complexity. They're not mandatory.
With docker you'll probably bind container port to the host. With kubernetes you can create Service of type NodePort and it's exactly the same.
Load balancing: I'm not really sure what do you mean, what do you use for docker load balancing? Just expose your kubernetes host to the Internet and that's about it. Or hide it behind separate reverse proxy, if you want.
Mounting directory from the host is supported with kubernetes, no problems here. Use hostPath volume in the pod spec.