First thing I have heard about NetApp. Seems to be some enterprise focused company, with more than one product. Not sure which product of theirs you refer to.

Synology, TrueNAS and Proxmox probably also have NFS support I would assume, and they definitely have Samba. Those are more relevant to me personally.

I just run a normal headless Linux distro on my NAS computer, I don't see the point of a specialised NAS distro. It too could have NFS if I wanted it, but it currently has Samba, because it is easier and works better.

So in conclusion, I'm not sure what your point is? Doesn't NetApp support anything except NFS?