If you are having problems with local streaming from a NAS using Asset you should sort out your home network. The 1st gen NDX does not have good WiFi performance, and will almost certainly benefit from a wired connection to your router. There are various workarounds using wireless bridges and/or mesh WiFi which may help, but the cheapest and most reliable way is to use a good old fashioned Ethernet cable.
BubbleUPnP Server can be a great way to improve reliability of web streaming services like Tidal and Qobuz, but they won’t compensate for poor LAN performance.
I don’t think this is the Naim app that has wireless connection issues, maybe it’s how you have implemented you local network.
However if you are saying your NDX is connected over wireless, I would look into that as ‘legacy’ streamers are all a bit flaky using wireless.
My NDX has been rock solid with an ethernet connection, whereas on the odd occasion I’ve used wireless, it’s had connectivity losses.
I agree that the ideal solution would be to run a cable but it is not really possible with my current setup. However when the streamer disappears I can get it back by pressing random buttons on the remote and then issuing a ping command from the fing app. This is not ideal but I can live with it.
I had a look at BubbleUPNP and I discover it’s not a replacement for the Naim App.
If you run BubbleUPnP Server on your NAS, you can use it to make your streamer OpenHome compatible and then use control apps such as Linn’s to control it. Whether this would help with your discovery problems I rather doubt, though.