Open Settings, Privacy, Local Network, look for the NoMachine app in the list and grant the permission.
Yes, that was it! Setting “Privacy, Local Network” to on for NoMachine is all that’s required for this to work. I.e. with “Network browsing” set to off in NoMachine’s settings that just disables the auto-discovery of NoMachine servers. All of my statically defined connections continue to work.
I thought there might be an Apple setting affecting this, but when you search the settings app for “NoMachine” you don’t get any results.
Thanks for much for the quick fix.