NFSv4 + Kerberos on OpenWRT 19.07

I am trying to get a kerberized NFSv4 to work on a Linksys WRT1900ACS with OpenWRT 19.07.

Both services work "separately", i.e., I can mount a NFSv4 share with sec=sys, and I can obtain TGTs and service tickets (nfs/myserver@DOMAIN). But they won't work together.

I am pretty sure one of the reasons is that there are no gssd nor idmapd executables in the nfs-kernel-server package, nor in any other package that seems appropriate. Are they available in some other package or repo, or does this work differently on OpenWRT? Did anyone get this to work?

Many thanks!