Static Mapping for NFS is used for mapping a local user or group id to a remote user or remote id. So you dont have to sync. user database on both machines.
Make the file /etc/nfs/maps.map and put this lines in
uid 1000 0
that will map remote userid 1000 to local userid 0 (root).
you can add as many as you want, use “gid” if it’s group id’s
and then in /etc/exports