I have had various incarnations of Naim streamers and have always used Asset UpNp with no real issues. I currently have 2 Atoms and something in the Kate’s updates seems to have slowed down the discovery process. When starting the Naim app on my iPhone 14 it waits anything up to 30s until the servers appear. It used to be instantaneous. Since every time you reopen the app it waits, it is much more painful than it used to be.
I’ve not had any issues on any of my iOS devices since the update. Sounds like you might need to go through some complete reboots of your devices. I’d probably start with your iPhone
I’d start with the router, all off, wait 5 mins so the ISP logs you’re off line, start the router first, let it finish its start/connect process, then one at a time, NAS or whatever, then Atom, then control devise (iPhone or whatever)
Have rebooted all the network componets and servers in various orders with no difference. will try with bigger gaps .
If that doesn’t work, it might be worth a reset to Factory Default Settings. That will lose your presets, but has been known to correct discovery issues.