NFS-Cache is a specific cache for NFS, and does not represent all caching that can be done of files over NFS. "Direct I/O" is also a specific thing, and should not be generalized in the meanings of "direct" and "I/O".
Let's skip those entirely for now as I cannot simply explain either. I doubt either will matter in your use case, but look back if performance lags.
One laptop accessing one NFS share will have good performance on a quite local network.
NFS is an old protocol that is robust and used frequently. NFSv3 is not encrypted. NFSv4 has support for encryption. (ZeroTier can handle the encryption.)
SSHFS is a pseudo file system layered over SSH. SSH handles encryption. SSHFS is maybe 15 years old and is aimed at convenience. SSH is largely aimed at moving streams of text between two points securely. Maybe it is faster now than it was.
If there is sufficient RAM on the laptop, Linux will cache a lot of metadata in other cache layers without NFS-Cache.