Is there anything like this that could run off a phone?
If you care about your data and want to truly own it, you should run your own relay.
If you're not a developer, nostr-relay-tray is perfect for you. Just grab an old computer, install it, and let it run quietly in the corner of your room. It’s simple.
Download nostr-relay-tray today and take control of your data!
1. Download the appropriate installer from https://github.com/CodyTseng/nostr-relay-tray/releases and install it.
2. Open nostr-relay-tray.
3. Go to "Proxy", and toggle the switch.
4. Add the public address to your relay list.
5. To prevent receiving spam events, enable WoT (Web of Trust) under "WoT & PoW".
Discussion
If you're using an Android device, you could try https://github.com/greenart7c3/Citrine