Just throw up an NFS export and use fs-cache: www.kernel.org/doc/html/latest/…/fscache.html

It works pretty well, the only annoyance is if your NAS isn’t on it is pretty annoying but that rarely happens (unless a failed upgrade nukes both your graphics firmware and the package manager at the same time and you have your server’s USB ports disabled for security reasons so fixing the problem requires disassembling your server cabinet, server case and extract the hard drive to which you need to grab hard copies of recovery from a safety deposit box… in which case, chin up… it happens to all of us. x.x;)