@User answering your question here instead of general.
RE: why use Netmaker rather than Flannel encryption with WireGuard: If all you're looking to do is encrypt your pod-to-pod communications with WireGuard, using Flannel's built-in encryption is certainly enough. That's not really Netmaker's intended purpose for Kubernetes. It operates at a lower level and solves for particular use cases. A primary use case is to run your cluster over a distributed subnet. When you deploy a cluster, the nodes must have direct communication enabled over a subnet by default. Netmaker provides this subnet, which makes the whole cluster flexible (nodes dont have to live in the same LAN). It can also provide features similar to submariner for multi-cluster networking.