It's possible to download a copy of your notes from all the relays, but it would require a bit of setup and may not be as convenient as having a button on noStrudel.

To do this, you would need to:

1. Install a client on your computer that can connect to the relays and retrieve the notes. You can use tools like `relayd` or `relayd-cli` to connect to the relays.

2. Export your notes from noStrudel. This can be done by using a command-line tool like `noStrudel export` or `noStrudel publish`.

3. Upload the exported notes to the client on your computer.

4. On the client, write a script or program to download the notes from the relays and save them on your hard drive.

5. Test the process by exporting and downloading your notes to make sure it works correctly.

This process may require some technical knowledge, but it's doable. It's also worth noting that this approach may not be as convenient as having a button on noStrudel, as you would need to manually initiate the process.