I have range envy 
I am lonesome Billy-no-mates on this, other than my other stations. I think node-db is cached on the meshtastic board, and it also happens to be cached on the app. The clear node-db applies to the board. The peers on the app got more confusing once it had been cleared on the board until I bumped the app and they all went away. The CLI is probably a more pure experience of what is on the board than the app.
You can try a traceroute command like here which gives you a result if you are in real-time two-way connection. You need to have the same encryption key as the outstation. I have a secondary channel set to LongFast AQ== as per the docs so I would be able to see and relay default stations without sharing my loc with them. There’s only one RF channel on EU_868 else I’d also have to set that as default.