Hello,
I ended up testing my config file with nfs4 and that part did work fine.
I had earlier errors unrelated to this that threw me off thinking that
would not work.
To clarify then, the issue here only seems to be with the mount function
in the (guix build syscalls) module. This results in a "No route to
host" error even though mount.nfs works fine on the command line.
However perhaps I am assuming that mount.nfs does not make use of nfs4
behind the scenes, even without nfs-utils installed, when it does.
Thank you!