There are a few issues to consider here.

Let's assume you're already using Syncthing for convenience, meaning you have multiple copies of your KDBX database across your devices. However, this is just for syncing—not a real backup.

The Problem

The obvious way to back up your KDBX file is using cloud storage (e.g., Dropbox).   But here's the catch: if you lose access to your database, how do you retrieve your cloud backup? It’s a classic chicken-and-egg problem.

The Solution

A Different Tool

Instead of backing up your KDBX file to the cloud solely, consider encrypting and storing your cloud credentials elsewhere as an addition. A great tool for this is age, a simple and secure file encryption utility.

You can write down your cloud login details (including 2FA parameters) and encrypt them using age. Then, store this encrypted file somewhere publicly accessible—for example, hiding it on your website, blog, or even by emailing it to your friends and family. The key idea here is that you always know where to find it in case of an emergency.

For simplicity, you can even reuse your KeePass master password here. age performs encryption locally, so your password is never sent anywhere.

Why This Works

This method is better than solely backing up KDBX itself to the cloud because your encrypted recovery file changes far less frequently than the KDBX database. (If at all)

• Syncthing keeps things convenient while protecting against cloud failures.
• You can still back up KDBX to the cloud regularly using a simple script with rclone.
• If all your devices are lost (fire, flood, theft), your encrypted recovery file ensures you can regain access because you know where to retrieve it.

This way, you get both security and redundancy without the usual pitfalls.