Is there some kind of setting or call I could add to haven relay that would make this work? 

 We basically have to options: 
- Auth with a key used by the Push Server itself. Everybody would have to white list that key to download their own DMs. 
- Change the relay spec to allow a REQ, authed in the past by the user, like on https://github.com/nostr-protocol/nips/pull/1148/ 

 Or maybe DM relays should have their own Push system and each user must set it up in a way that it sends to their NTFY handler when they receive a new one. 

Not as easy as Google Play notifications, but it can work.  

 NTFY has been great and I think the community as a whole should adopt it more heavily  

 Who's got the best guide on relay visibility setup these days? 

 nostr:nprofile1qqsyvrp9u6p0mfur9dfdru3d853tx9mdjuhkphxuxgfwmryja7zsvhqpzamhxue69uhhv6t5daezumn0wd68yvfwvdhk6tcppemhxue69uhkummn9ekx7mp0qyghwumn8ghj7mn0wd68ytnhd9hx2tcewvzaw, do you have any recommendations for 'trustworthy' public but hidden relays for DMs? This is the only part of your original post that I still couldn't fully grasp.

Also, while inefficient, is there anything stopping us from implementing a short polling-based flow in the client itself using the user's nsec (e.g., pulling DMs in the background every 'configurable' amount of seconds, defaulting to 600s) 

 One example of a hidden relay would be your own relay from relay.tools but we don't have many settings to make it work better yet.  

 Got it, thanks! What do you think about the short polling idea? It’d use a bit more bandwidth and battery, but users wouldn’t have to whitelist an intermediate. Plus, it’d take some load off Amethyst’s notification servers. I’d be cool with that trade-off if it’s technically doable. 

 I don't know... People already complain we use too much battery today. Keeping a service running will definitely make things worse.. 

 Got it. It would meed to be optional of course, and likely off by default. But I would enable it if It meant I could use mh personal relay exclusively for DMs and still receive notifications.  

 Interesting. Maybe we can start to develop it to see how it goes. 

 Yes, for sure. If you don't get to it first, I might take a stab at it myself in a couple of weeks. I'm not much of a mobile developer, but hopefully, my "backend" Kotlin skills can at least get it to a first draft. 

 I would be willing to try it regardless of battery consumption, if you give it a whirl. I'm using a personal relay from relay.tools exclusively for everything and get no notifications at all.  

 I am not an expert in Push Notifications staff but isn't it common to send something generic like "You have a new message" instead of leaking plaintext of the real event? 

 If only those two relays are there, we don't even know when you have a new event. :) 

 based