I have this setup, please do the machine/folder names translation according to your case.
In /etc/exports on server side (mine is a centos 7):
From client side (macOS Catalina Version 10.15.6)
$ sudo mount -t nfs -o resvport,rw,noowners 172.20.0.100:/workspace_guest/...
Do you have the NFS client utilities installed on the Linux system? The error message from your Linux system states that /sbin/mount.nfs isn't present, which suggests that the NFS client utilities are missing. On Debian/Ubuntu systems they're in package nfs-common - install that package and see if the mount then succeeds.
If you're all you're interested in ...