How to force NFS to keep files on client side?
Solution 1:
No, you cant keep files on your client by using NFS - NFS (As Network File Server implies) stores the files on the server and allows them to be accessed/modified by client.
NFS is an ancient technology which is much simpler then systems that syndicate files. You might want to investigate alternative technologies like rsync and Nextcloud, but if this is development work as in coding, GIT is the go-to solution.